G Geometry and measures — coverage pack

25 specification leaves · notes, questions, answers and worked methods

G1 · Use conventional terms/notations: points, lines, vertices, edges, planes, parallel and perpendicular lines, right angles, polygons; standard triangle labelling; draw diagrams from written description

  • Use precise geometric language: a vertex is a corner, an edge joins vertices, parallel lines never meet, and perpendicular lines meet at a right angle.
  • Label an angle by placing its vertex in the middle, so ABC\angle ABC is the angle at BB; in triangle ABCABC, side ABAB is opposite vertex CC.
  • Build a diagram one instruction at a time, marking equal lengths, parallel lines and right angles with conventional symbols rather than relying on appearance.
  • A common error is to assume a sketch is drawn to scale; only stated facts and marked relationships may be used.

Tier 1 · Easy

  1. 1. In triangle PQRPQR, which vertex is opposite the side PRPR?[1 mark]

    Answer

    • Vertex QQ

    Method: The side PRPR joins vertices PP and RR. The remaining vertex is QQ, so QQ is opposite PRPR.

Tier 2 · Standard

  1. 1. Lines ABAB and CDCD are parallel. A line through EE meets ABAB at FF at a right angle. State the relationship between EFEF and CDCD.[1 mark]

    Answer

    • EFEF is perpendicular to CDCD.

    Method: Because ABCDAB\parallel CD, a line perpendicular to ABAB is also perpendicular to CDCD. Therefore EFCDEF\perp CD.

Tier 3 · Hard

  1. 1. Draw quadrilateral ABCDABCD with ABCDAB\parallel CD. Draw diagonal ACAC. Mark a point EE on ACAC, then draw the line through EE perpendicular to ABAB, meeting ABAB at FF and CDCD at GG.[3 marks]

    Answer

    • A correctly labelled diagram with ABCDAB\parallel CD, A,E,CA,E,C collinear, F,E,GF,E,G collinear, and right-angle marks at FF and GG.

    Method: Draw and arrow-mark the parallel sides ABAB and CDCD, then join AA to CC. Place EE on ACAC. Through EE, draw one straight line meeting ABAB at FF and CDCD at GG, and mark both perpendicular intersections as right angles.

G2 · Use standard ruler and compass constructions (perpendicular bisector, perpendicular from/at a point, angle bisector); construct figures, solve loci problems; perpendicular distance is shortest

  • A perpendicular bisector crosses a segment at its midpoint at 9090^\circ; every point on it is equidistant from the segment's endpoints.
  • Construct an angle bisector using equal-radius arcs from the vertex and then intersecting arcs from the two arms; points on it are equidistant from the arms.
  • Translate locus conditions into standard boundaries: a fixed distance from a point gives a circle, while a fixed distance from a straight line gives two parallel lines.
  • Keep compass arcs visible and do not measure to replace a construction; the perpendicular distance to a line is the shortest distance.

Tier 1 · Easy

  1. 1. Describe how to construct the perpendicular bisector of a line segment ABAB using a ruler and compasses.[2 marks]

    Answer

    • Draw equal-radius arcs from AA and BB that meet above and below ABAB, then join the two arc intersections.

    Method: Set the compass radius to more than half of ABAB. Without changing it, draw arcs centred at AA and BB so that they intersect twice. A straight line through the intersections is the perpendicular bisector of ABAB.

Tier 2 · Standard

  1. 1. Two straight paths meet at OO. A lamp must be equally distant from the two paths and no more than 66 m from OO. Describe the locus of possible positions inside the angle between the paths.[3 marks]

    Answer

    • The part of the internal angle bisector from OO up to and including the point 66 m from OO.

    Method: Points equidistant from two intersecting lines lie on an angle bisector. Restricting the distance from OO to at most 66 m keeps only the segment of the internal bisector inside the circle centred at OO with radius 66 m.

Tier 3 · Hard

  1. 1. Points AA and BB are 88 cm apart. A point PP must satisfy PA=PBPA=PB and PA5PA\leq5 cm. Describe and construct the complete locus of PP.[4 marks]

    Answer

    • The part of the perpendicular bisector of ABAB lying inside or on both circles of radius 55 cm centred at AA and BB; it is the segment joining the circles' two intersection points.

    Method: Construct the perpendicular bisector of ABAB because PA=PBPA=PB. Draw circles of radius 55 cm centred at AA and BB. The condition PA5PA\leq5 keeps points inside both circles, so the required locus is the perpendicular-bisector segment between their two intersections.

G3 · Apply angles at a point, on a straight line, vertically opposite angles; use alternate and corresponding angles on parallel lines; derive and use the angle sum of a triangle and of any polygon

  • Angles at a point sum to 360360^\circ, angles on a straight line sum to 180180^\circ, and vertically opposite angles are equal.
  • When a transversal crosses parallel lines, alternate and corresponding angles are equal; co-interior angles sum to 180180^\circ.
  • Splitting an nn-sided polygon into n2n-2 triangles gives an interior-angle sum of (n2)×180(n-2)\times180^\circ.
  • Do not quote alternate or corresponding angles unless the relevant lines are stated or shown to be parallel, and name the angle fact used.

Tier 1 · Easy

  1. 1. Two adjacent angles on a straight line are 6363^\circ and xx^\circ. Work out xx.[1 mark]

    Answer

    • 117117^\circ

    Method: Angles on a straight line total 180180^\circ, so x=18063=117x=180^\circ-63^\circ=117^\circ.

Tier 2 · Standard

  1. 1. Two parallel lines are crossed by a transversal. A pair of alternate angles are (4x+7)(4x+7)^\circ and (7x38)(7x-38)^\circ. Find xx and the size of these angles.[3 marks]

    Answer

    • x=15x=15
    • 6767^\circ

    Method: Alternate angles between parallel lines are equal, so 4x+7=7x384x+7=7x-38. Hence 45=3x45=3x and x=15x=15. Substitution gives 4(15)+7=674(15)+7=67^\circ.

Tier 3 · Hard

  1. 1. A polygon has 1313 sides. Twelve of its interior angles are each 155155^\circ. Work out the remaining interior angle.[4 marks]

    Answer

    • 120120^\circ

    Method: The interior-angle sum is (132)×180=1980(13-2)\times180^\circ=1980^\circ. The twelve known angles total 12×155=186012\times155^\circ=1860^\circ. The remaining angle is 19801860=1201980^\circ-1860^\circ=120^\circ.

G4 · Derive and apply properties and definitions of special quadrilaterals (square, rectangle, parallelogram, trapezium, kite, rhombus), triangles and other plane figures using appropriate language

  • Classify a shape from properties that must always hold: for example, a parallelogram has two pairs of parallel opposite sides and a trapezium has one pair of parallel sides.
  • A rectangle has four right angles, a rhombus has four equal sides, and a square satisfies both definitions as well as being a parallelogram.
  • Use diagonal properties carefully: parallelogram diagonals bisect each other, rectangle diagonals are also equal, and rhombus diagonals are also perpendicular.
  • A common error is to use a property that is merely possible rather than guaranteed; one diagram cannot establish a definition.

Tier 1 · Easy

  1. 1. Name the quadrilateral that has exactly one pair of parallel sides.[1 mark]

    Answer

    • Trapezium

    Method: A quadrilateral with exactly one pair of parallel sides is a trapezium.

Tier 2 · Standard

  1. 1. One interior angle of a rhombus is 6868^\circ. Work out the other three interior angles.[2 marks]

    Answer

    • 112112^\circ, 6868^\circ, 112112^\circ

    Method: Opposite angles in a rhombus are equal and adjacent angles sum to 180180^\circ. The opposite angle is 6868^\circ, and each adjacent angle is 18068=112180^\circ-68^\circ=112^\circ.

Tier 3 · Hard

  1. 1. The diagonals of quadrilateral WXYZWXYZ bisect each other and are equal in length. Explain why WXYZWXYZ must be a rectangle, and why the information does not prove that it is a square.[3 marks]

    Answer

    • Diagonals that bisect each other make the quadrilateral a parallelogram; equal diagonals then make it a rectangle. A square would additionally require four equal sides or perpendicular diagonals, which has not been given.

    Method: First use the converse parallelogram property: diagonals that bisect each other establish a parallelogram. In a parallelogram, equal diagonals establish a rectangle. Equal diagonals alone do not establish equal sides or perpendicular diagonals, so a non-square rectangle remains possible.

G5 · Use the basic congruence criteria for triangles (SSS, SAS, ASA, RHS)

  • Congruent triangles are identical in size and shape, so all corresponding sides and angles are equal.
  • Use SSS for three side pairs, SAS for two side pairs and the included angle, ASA for two angle pairs and a side, and RHS for right triangles with equal hypotenuse and one other side.
  • Write vertices in corresponding order when stating congruence, then transfer only matching sides or angles.
  • AAA proves similarity, not congruence, and SSA is not a valid general congruence test.

Tier 1 · Easy

  1. 1. Triangle ABCABC has side lengths 55 cm, 77 cm and 99 cm. Triangle PQRPQR has side lengths 55 cm, 77 cm and 99 cm. State the congruence criterion.[1 mark]

    Answer

    • SSS

    Method: All three side lengths of one triangle match all three side lengths of the other, so the criterion is SSS.

Tier 2 · Standard

  1. 1. Triangles ABCABC and DEFDEF are right-angled at BB and EE. Also AC=DF=13AC=DF=13 cm and AB=DE=5AB=DE=5 cm. Explain why the triangles are congruent.[2 marks]

    Answer

    • They are congruent by RHS.

    Method: Both triangles are right-angled, their hypotenuses ACAC and DFDF are equal, and one corresponding pair of shorter sides ABAB and DEDE is equal. Therefore the triangles are congruent by RHS.

Tier 3 · Hard

  1. 1. In quadrilateral ABCDABCD, diagonal ACAC is drawn. Given that AB=ADAB=AD and BAC=CAD\angle BAC=\angle CAD, prove that BC=CDBC=CD.[3 marks]

    Answer

    • BC=CDBC=CD

    Method: Compare triangles BACBAC and DACDAC. We have AB=ADAB=AD, ACAC is common, and the included angles BAC\angle BAC and CAD\angle CAD are equal. The triangles are congruent by SAS, so corresponding sides BCBC and DCDC are equal.

G6 · Apply angle facts, congruence, similarity and quadrilateral properties to derive results about angles and sides, incl. Pythagoras' theorem and isosceles base angles, and obtain simple proofs

  • In an isosceles triangle, equal sides face equal angles; the converse also holds, so equal angles face equal sides.
  • For a right-angled triangle, use a2+b2=c2a^2+b^2=c^2 with cc opposite the right angle, and take the positive square root for a length.
  • A geometric proof should form a connected chain in which every equality follows from a stated angle fact, shape property, similarity or congruence result.
  • Do not use the fact being proved as a reason, and do not infer equal sides or angles just because they look equal in a sketch.

Tier 1 · Easy

  1. 1. Triangle ABCABC is isosceles with AB=ACAB=AC. Angle BB is 4747^\circ. Work out angle AA.[2 marks]

    Answer

    • 8686^\circ

    Method: Equal sides face equal angles, so angle CC is also 4747^\circ. The angles in a triangle sum to 180180^\circ, giving A=1804747=86A=180^\circ-47^\circ-47^\circ=86^\circ.

Tier 2 · Standard

  1. 1. A right-angled triangle has perpendicular sides 99 cm and 1212 cm. Work out the length of its hypotenuse.[3 marks]

    Answer

    • 1515 cm

    Method: By Pythagoras' theorem, c2=92+122=81+144=225c^2=9^2+12^2=81+144=225. Therefore c=225=15c=\sqrt{225}=15 cm.

Tier 3 · Hard

  1. 1. In quadrilateral ABCDABCD, ABCDAB\parallel CD and AB=CDAB=CD. Diagonal ACAC is drawn. Prove that BC=ADBC=AD.[4 marks]

    Answer

    • BC=ADBC=AD

    Method: Because ABCDAB\parallel CD, BAC=DCA\angle BAC=\angle DCA as alternate angles. Also AB=CDAB=CD and ACAC is common. Thus triangles BACBAC and DCADCA are congruent by SAS. Corresponding sides BCBC and DADA are therefore equal.

G7 · Identify, describe and construct congruent and similar shapes, incl. on coordinate axes, by rotation, reflection, translation and enlargement (including fractional and negative scale factors)

  • Describe a translation by a vector, a rotation by its centre, angle and direction, a reflection by its mirror line, and an enlargement by its centre and scale factor.
  • Translations, rotations and reflections preserve lengths and angles, so the image is congruent to the object; an enlargement preserves angles and scales every length by the same factor.
  • For an enlargement about centre CC, multiply the vector from CC to each point by the scale factor; a negative factor places the image on the opposite side of CC.
  • A common error is to omit part of a full transformation description or to multiply coordinates directly when the centre of enlargement is not the origin.

Tier 1 · Easy

  1. 1. Point A(3,4)A(-3,4) is translated by the vector (52)\begin{pmatrix}5\\-2\end{pmatrix}. Find the coordinates of its image.[2 marks]

    Answer

    • (2,2)(2,2)

    Method: Add the vector components to the coordinates: (3+5,42)=(2,2)(-3+5,4-2)=(2,2).

Tier 2 · Standard

  1. 1. Point P(4,1)P(4,-1) is rotated 9090^\circ anticlockwise about the origin. Find the coordinates of its image PP'.[2 marks]

    Answer

    • P(1,4)P'(1,4)

    Method: A 9090^\circ anticlockwise rotation about the origin maps (x,y)(x,y) to (y,x)(-y,x). Therefore (4,1)(4,-1) maps to (1,4)(1,4).

Tier 3 · Hard

  1. 1. Triangle ABCABC has vertices A(6,3)A(6,3), B(0,5)B(0,5) and C(2,1)C(-2,-1). It is enlarged by scale factor 12-\frac12 about centre (2,1)(2,-1). Find the three image coordinates.[4 marks]

    Answer

    • A(0,3)A'(0,-3)
    • B(3,4)B'(3,-4)
    • C(4,1)C'(4,-1)

    Method: Subtract the centre, multiply by 12-\frac12, then add the centre. For AA, (4,4)(2,2)(4,4)\mapsto(-2,-2), giving (0,3)(0,-3). For BB, (2,6)(1,3)(-2,6)\mapsto(1,-3), giving (3,4)(3,-4). For CC, (4,0)(2,0)(-4,0)\mapsto(2,0), giving (4,1)(4,-1).

G8 · Describe the changes and invariance achieved by combinations of rotations, reflections and translations [Higher only]

  • Track a combination in the stated order: the output of the first transformation is the input to the next.
  • Two translations combine by adding their vectors, while some pairs of reflections combine to form a rotation or a translation.
  • Rotations, reflections and translations preserve lengths, angle sizes, area and parallelism; reflections reverse orientation, whereas rotations and translations preserve it.
  • Do not reverse the order of a combination: transformations need not commute, so changing the order can change the final image.

Tier 1 · Easy

  1. 1. A shape is rotated and then translated. State two properties of the shape that must remain invariant.[2 marks]

    Answer

    • Any two of: side lengths, angle sizes, area, parallelism, or orientation remain unchanged.

    Method: Both a rotation and a translation are rigid transformations. Each preserves lengths and angles, so it also preserves area and parallel lines; neither reverses orientation.

Tier 2 · Standard

  1. 1. A shape is translated first by (32)\begin{pmatrix}3\\-2\end{pmatrix} and then by (57)\begin{pmatrix}-5\\7\end{pmatrix}. Describe the single equivalent transformation.[2 marks]

    Answer

    • A translation by (25)\begin{pmatrix}-2\\5\end{pmatrix}.

    Method: Add the translation vectors component by component: (32)+(57)=(25)\begin{pmatrix}3\\-2\end{pmatrix}+\begin{pmatrix}-5\\7\end{pmatrix}=\begin{pmatrix}-2\\5\end{pmatrix}.

Tier 3 · Hard

  1. 1. A shape is reflected in the xx-axis and then reflected in the line y=xy=x. Describe the single equivalent transformation and state whether orientation is preserved.[4 marks]

    Answer

    • A rotation of 9090^\circ anticlockwise about the origin; orientation is preserved.

    Method: The first reflection maps (x,y)(x,y) to (x,y)(x,-y). Reflection in y=xy=x then swaps the coordinates, giving (y,x)(-y,x). This is the coordinate rule for a 9090^\circ anticlockwise rotation about the origin. A rotation preserves orientation.

G9 · Identify and apply circle definitions and properties, including: centre, radius, chord, diameter, circumference, tangent, arc, sector and segment

  • A radius joins the centre to the circumference, a diameter is a chord through the centre, and every diameter is twice the radius.
  • A tangent touches a circle at one point, while a chord joins two points on the circumference; an arc is a portion of the circumference.
  • A sector is bounded by two radii and an arc, whereas a segment is bounded by a chord and an arc.
  • Do not call the curved boundary a circle: the circumference is the boundary, while the circle includes the region inside it.

Tier 1 · Easy

  1. 1. A circle has radius 6.56.5 cm. Write down its diameter.[1 mark]

    Answer

    • 1313 cm

    Method: The diameter is twice the radius, so d=2×6.5=13d=2\times6.5=13 cm.

Tier 2 · Standard

  1. 1. A straight segment joins two points on a circle but does not pass through its centre. Another straight line meets the circle at exactly one point. Give the geometric name of each.[2 marks]

    Answer

    • The segment is a chord; the line is a tangent.

    Method: A segment whose endpoints lie on the circumference is a chord. A line meeting a circle at exactly one point is a tangent.

Tier 3 · Hard

  1. 1. A circle is centred at OO. Distinct points AA and BB are on its circumference, and ABAB is not a diameter. Describe precisely the boundaries of the minor sector AOBAOB and the minor segment cut off by ABAB.[3 marks]

    Answer

    • The minor sector is bounded by radii OAOA and OBOB and the minor arc ABAB; the minor segment is bounded by chord ABAB and the minor arc ABAB.

    Method: A sector uses two radii plus their connecting arc. A segment uses a chord plus its corresponding arc. Selecting the shorter arc ABAB gives the minor sector and minor segment.

G10 · Apply and prove the standard circle theorems concerning angles, radii, tangents and chords, and use them to prove related results [Higher only]

  • The angle at the centre is twice the angle at the circumference standing on the same arc; angles in the same segment are equal, and an angle in a semicircle is 9090^\circ.
  • Opposite angles in a cyclic quadrilateral sum to 180180^\circ, and the alternate segment theorem links the angle between a tangent and chord to the angle in the opposite segment.
  • A radius is perpendicular to a tangent at the point of contact; tangents from the same external point are equal, and the perpendicular from the centre bisects a chord.
  • Always identify the same chord or arc before applying an angle theorem, and state the theorem as the reason rather than quoting an unsupported angle.

Tier 1 · Easy

  1. 1. ABAB is a diameter of a circle and CC is another point on the circumference. Find ACB\angle ACB.[1 mark]

    Answer

    • 9090^\circ

    Method: The angle in a semicircle is 9090^\circ, so ACB=90\angle ACB=90^\circ.

Tier 2 · Standard

  1. 1. In a circle with centre OO, the angle AOBAOB is 124124^\circ. Point CC lies on the major arc ABAB. Work out ACB\angle ACB.[2 marks]

    Answer

    • 6262^\circ

    Method: Both angles stand on the minor arc ABAB. The angle at the centre is twice the angle at the circumference, so ACB=124÷2=62\angle ACB=124^\circ\div2=62^\circ.

Tier 3 · Hard

  1. 1. From a point PP outside a circle with centre OO, tangents touch the circle at AA and BB. Prove that PA=PBPA=PB and that OPOP bisects APB\angle APB.[4 marks]

    Answer

    • PA=PBPA=PB and APO=OPB\angle APO=\angle OPB

    Method: Radii meet tangents at right angles, so triangles OAPOAP and OBPOBP are right-angled. They have equal hypotenuse OPOP and equal radii OA=OBOA=OB, so they are congruent by RHS. Corresponding parts then give PA=PBPA=PB and APO=OPB\angle APO=\angle OPB, proving that OPOP bisects APB\angle APB.

G11 · Solve geometrical problems on coordinate axes

  • Use coordinate differences to find horizontal and vertical lengths, and use the midpoint formula by averaging the two xx-coordinates and the two yy-coordinates.
  • The distance between (x1,y1)(x_1,y_1) and (x2,y2)(x_2,y_2) is (x2x1)2+(y2y1)2\sqrt{(x_2-x_1)^2+(y_2-y_1)^2} by Pythagoras' theorem.
  • Gradients can establish geometry: equal gradients show parallel lines, while gradients with product 1-1 show perpendicular non-vertical lines.
  • Keep signs when subtracting negative coordinates, and do not read a length directly from a sketch that is not drawn to scale.

Tier 1 · Easy

  1. 1. Find the midpoint of the line segment joining (5,2)(-5,2) to (7,8)(7,8).[2 marks]

    Answer

    • (1,5)(1,5)

    Method: Average the coordinates: x=(5+7)/2=1x=(-5+7)/2=1 and y=(2+8)/2=5y=(2+8)/2=5. The midpoint is (1,5)(1,5).

Tier 2 · Standard

  1. 1. Points A(1,4)A(-1,4) and B(5,4)B(5,-4) are joined. Find the exact length ABAB.[3 marks]

    Answer

    • 1010

    Method: The coordinate changes are 5(1)=65-(-1)=6 and 44=8-4-4=-8. Therefore AB=62+(8)2=36+64=100=10AB=\sqrt{6^2+(-8)^2}=\sqrt{36+64}=\sqrt{100}=10.

Tier 3 · Hard

  1. 1. Triangle ABCABC has vertices A(2,1)A(-2,1), B(4,3)B(4,3) and C(2,9)C(2,9). Show that the triangle is right-angled and isosceles, then work out its area.[5 marks]

    Answer

    • Right-angled at BB
    • AB=BC=210AB=BC=2\sqrt{10}
    • Area =20=20 square units

    Method: The gradients are mAB=2/6=1/3m_{AB}=2/6=1/3 and mBC=6/(2)=3m_{BC}=6/(-2)=-3, whose product is 1-1, so the angle at BB is 9090^\circ. Also AB=62+22=40=210AB=\sqrt{6^2+2^2}=\sqrt{40}=2\sqrt{10} and BC=(2)2+62=40=210BC=\sqrt{(-2)^2+6^2}=\sqrt{40}=2\sqrt{10}, so the triangle is isosceles. Its perpendicular equal sides have area 12(210)2=20\frac12(2\sqrt{10})^2=20 square units.

G12 · Identify properties of the faces, surfaces, edges and vertices of: cubes, cuboids, prisms, cylinders, pyramids, cones and spheres

  • A face is flat, a curved surface is not a face, an edge is where surfaces meet, and a vertex is a point where edges meet.
  • An nn-sided prism has two congruent polygonal ends and nn rectangular side faces, giving n+2n+2 faces, 3n3n edges and 2n2n vertices.
  • A pyramid has one polygonal base and triangular faces meeting at one apex; a cone has one circular base, one curved surface and one vertex.
  • Count each feature once, especially hidden edges, and do not give a sphere or cylinder vertices where no edges meet.

Tier 1 · Easy

  1. 1. Write down the number of faces and the number of vertices of a triangular prism.[2 marks]

    Answer

    • 55 faces
    • 66 vertices

    Method: A triangular prism has two triangular faces and three rectangular faces, making 55 faces. Its two triangular ends have 3+3=63+3=6 vertices.

Tier 2 · Standard

  1. 1. A solid has one circular plane face, one curved surface, one circular edge and one vertex. Name the solid.[2 marks]

    Answer

    • Cone

    Method: The circular base is the one plane face, its rim is the circular edge, the side is curved, and the surfaces meet at one apex. These are the properties of a cone.

Tier 3 · Hard

  1. 1. A prism has a regular 99-sided polygon as each end. Work out its numbers of faces, edges and vertices.[3 marks]

    Answer

    • 1111 faces
    • 2727 edges
    • 1818 vertices

    Method: For an nn-sided prism, the counts are n+2n+2 faces, 3n3n edges and 2n2n vertices. With n=9n=9, these are 1111 faces, 2727 edges and 1818 vertices.

G13 · Construct and interpret plans and elevations of 3D shapes

  • A plan is the view from directly above; a front or side elevation is an orthographic view from the stated horizontal direction.
  • Project corresponding corners with parallel construction lines so widths align between the plan and front elevation and depths align between the plan and side elevation.
  • For stacks of cubes, an elevation shows the greatest height visible in each column along that viewing direction, while a numbered plan records each stack height.
  • Do not add perspective or show hidden internal edges unless asked; plans and elevations use true lengths in their viewing plane.

Tier 1 · Easy

  1. 1. A cuboid is 88 cm long, 55 cm wide and 33 cm high. State the shape and dimensions of its plan.[2 marks]

    Answer

    • A rectangle 88 cm by 55 cm

    Method: The plan is viewed from above, so it shows length and width but not height. Therefore it is an 88 cm by 55 cm rectangle.

Tier 2 · Standard

  1. 1. A numbered plan of unit-cube stacks has two rows. From north to south, the rows are (2,1)(2,1) and (3,0)(3,0), with entries ordered west to east. Give the visible column heights in the front elevation viewed from the south and in the side elevation viewed from the east.[3 marks]

    Answer

    • Front elevation, west to east: (3,1)(3,1)
    • Side elevation, north to south: (2,3)(2,3)

    Method: From the south, take the greatest height in each west-east column: west gives max(2,3)=3\max(2,3)=3 and east gives max(1,0)=1\max(1,0)=1. From the east, take the greatest height in each north-south row: north gives max(2,1)=2\max(2,1)=2 and south gives max(3,0)=3\max(3,0)=3.

Tier 3 · Hard

  1. 1. A solid uses vertical stacks of unit cubes on all four cells of a 22 by 22 plan. Its front elevation viewed from the south has heights (3,2)(3,2) from west to east. Its side elevation viewed from the east has heights (2,3)(2,3) from north to south. Find the least possible number of cubes and give one numbered plan that achieves it.[4 marks]

    Answer

    • 77 cubes; for example, from north to south the plan rows can be (1,2)(1,2) and (3,1)(3,1), with entries west to east.

    Method: The height 33 required in both the west front column and south side row can be placed in the south-west cell. The height 22 required in both the east front column and north side row can be placed in the north-east cell. The other two occupied cells need at least one cube each, giving 3+2+1+1=73+2+1+1=7. The plan rows (1,2)(1,2) and (3,1)(3,1) have exactly the stated elevations.

G14 · Use standard units of measure and related concepts (length, area, volume/capacity, mass, time, money, etc.)

  • Standard units include millimetres, centimetres, metres and kilometres for length; square or cubic units for area and volume; litres for capacity; grams or kilograms for mass; and seconds, minutes or hours for time.
  • Convert every measurement to compatible units before calculating, remembering that area conversion factors are squared and volume conversion factors are cubed.
  • For example, because 1 m=100 cm1\text{ m}=100\text{ cm}, it follows that 1 m2=10000 cm21\text{ m}^2=10\,000\text{ cm}^2 and 1 m3=1000000 cm31\text{ m}^3=1\,000\,000\text{ cm}^3.
  • A common error is to use the linear conversion factor for an area or volume, such as multiplying square metres by 100100 instead of 1000010\,000 to obtain square centimetres.

Tier 1 · Easy

  1. 1. Convert 3.75 kg3.75\text{ kg} to grams.[1 mark]

    Answer

    • 3750 g3750\text{ g}

    Method: There are 1000 g1000\text{ g} in 1 kg1\text{ kg}, so 3.75×1000=37503.75\times1000=3750. Therefore the mass is 3750 g3750\text{ g}.

Tier 2 · Standard

  1. 1. A rectangular water tank is 0.8 m0.8\text{ m} long, 0.5 m0.5\text{ m} wide and 0.6 m0.6\text{ m} high. It is 65%65\% full. Work out the volume of water in litres.[3 marks]

    Answer

    • 156156 litres

    Method: The full volume is 0.8×0.5×0.6=0.24 m30.8\times0.5\times0.6=0.24\text{ m}^3. The water occupies 0.65×0.24=0.156 m30.65\times0.24=0.156\text{ m}^3. Since 1 m3=10001\text{ m}^3=1000 litres, the volume is 0.156×1000=1560.156\times1000=156 litres.

Tier 3 · Hard

  1. 1. A floor measures 4.8 m4.8\text{ m} by 3.6 m3.6\text{ m}. Square tiles have side length 30 cm30\text{ cm} and are sold in boxes of 1212. A decorator buys at least 8%8\% more tiles than the exact number needed. Each box costs £14.7514.75. Work out the total cost.[5 marks]

    Answer

    • £265.50265.50

    Method: Each tile has side 0.30 m0.30\text{ m}, so its area is 0.302=0.09 m20.30^2=0.09\text{ m}^2. The floor area is 4.8×3.6=17.28 m24.8\times3.6=17.28\text{ m}^2, requiring exactly 17.28/0.09=19217.28/0.09=192 tiles. Including 8%8\% gives 192×1.08=207.36192\times1.08=207.36, so at least 208208 tiles are needed. Since 208/12=17.3208/12=17.\overline{3}, the decorator must buy 1818 boxes. The cost is 18×14.75=265.5018\times14.75=265.50, so the total is £265.50265.50.

G15 · Measure line segments and angles in geometric figures, including interpreting maps and scale drawings and use of bearings

  • Lengths and angles can be measured from an accurate drawing, while a map scale links a measured map distance to the corresponding real distance.
  • For a scale 1:n1:n, multiply a map length by nn to obtain the real length in the same units; bearings are measured clockwise from north and written using three figures.
  • For example, a clockwise angle of 5252^\circ from north is written as the bearing 052052^\circ, and the reverse bearing is 232232^\circ.
  • A common error is to measure a bearing anticlockwise or from an east-west line instead of clockwise from the north line at the starting point.

Tier 1 · Easy

  1. 1. A ray from point PP makes an angle of 6868^\circ clockwise from north. Write its bearing from PP.[1 mark]

    Answer

    • 068068^\circ

    Method: A bearing is the clockwise angle from north written with three figures. Therefore 6868^\circ is written as 068068^\circ.

Tier 2 · Standard

  1. 1. On a map with north at the top, point BB is 6 cm6\text{ cm} east and 8 cm8\text{ cm} north of point AA. The scale is 1:200001:20\,000. Work out the real straight-line distance from AA to BB and the bearing of BB from AA. Give the bearing to the nearest degree.[4 marks]

    Answer

    • 2 km2\text{ km}
    • 037037^\circ

    Method: The map distance is 62+82=10 cm\sqrt{6^2+8^2}=10\text{ cm}. The real distance is 10×20000=200000 cm=2 km10\times20\,000=200\,000\text{ cm}=2\text{ km}. If the bearing angle is θ\theta, then tanθ=6/8\tan\theta=6/8, so θ=36.9\theta=36.9^\circ. Written as a three-figure bearing to the nearest degree, this is 037037^\circ.

Tier 3 · Hard

  1. 1. On a scale drawing, a road of actual length 3.15 km3.15\text{ km} is represented by a line 8.4 cm8.4\text{ cm} long. Find the scale in the form 1:n1:n. Another road is 11.2 cm11.2\text{ cm} long on the same drawing. Work out its actual length in kilometres.[4 marks]

    Answer

    • 1:375001:37\,500
    • 4.2 km4.2\text{ km}

    Method: Convert 3.15 km3.15\text{ km} to 315000 cm315\,000\text{ cm}. The scale factor is 315000/8.4=37500315\,000/8.4=37\,500, so the scale is 1:375001:37\,500. The second road represents 11.2×37500=420000 cm=4.2 km11.2\times37\,500=420\,000\text{ cm}=4.2\text{ km}.

G16 · Know and apply formulae to calculate: area of triangles, parallelograms, trapezia; volume of cuboids and other right prisms (including cylinders)

  • Use A=12bhA=\frac12 bh for a triangle, A=bhA=bh for a parallelogram and A=12(a+b)hA=\frac12(a+b)h for a trapezium, where each height is perpendicular to the relevant base or parallel sides.
  • A right prism has a constant cross-section, so its volume is the area of that cross-section multiplied by the prism length; for a cylinder this gives V=πr2hV=\pi r^2h.
  • For example, a trapezium with parallel sides 55 and 99 and perpendicular height 44 has area 12(5+9)×4=28\frac12(5+9)\times4=28 square units.
  • A common error is to use a sloping side as the perpendicular height or to omit the factor of 12\frac12 in a triangle or trapezium calculation.

Tier 1 · Easy

  1. 1. A trapezium has parallel sides of lengths 7 cm7\text{ cm} and 13 cm13\text{ cm} and perpendicular height 6 cm6\text{ cm}. Work out its area.[2 marks]

    Answer

    • 60 cm260\text{ cm}^2

    Method: Use A=12(a+b)hA=\frac12(a+b)h. Then A=12(7+13)×6=12×20×6=60 cm2A=\frac12(7+13)\times6=\frac12\times20\times6=60\text{ cm}^2.

Tier 2 · Standard

  1. 1. A cylinder has radius 4 cm4\text{ cm} and height 9 cm9\text{ cm}. Work out its volume in terms of π\pi.[2 marks]

    Answer

    • 144π cm3144\pi\text{ cm}^3

    Method: The circular cross-section has area πr2=π(42)=16π cm2\pi r^2=\pi(4^2)=16\pi\text{ cm}^2. Multiply by the height: V=16π×9=144π cm3V=16\pi\times9=144\pi\text{ cm}^3.

Tier 3 · Hard

  1. 1. A right triangular prism is 10 cm10\text{ cm} long. Its triangular cross-section has base x cmx\text{ cm} and perpendicular height (x+2) cm(x+2)\text{ cm}. The volume is 600 cm3600\text{ cm}^3. Find xx.[4 marks]

    Answer

    • x=10x=10

    Method: The cross-sectional area is 12x(x+2)\frac12x(x+2). Hence 10×12x(x+2)=60010\times\frac12x(x+2)=600, so x(x+2)=120x(x+2)=120. This gives x2+2x120=0x^2+2x-120=0, which factorises to (x+12)(x10)=0(x+12)(x-10)=0. A length must be positive, so x=10x=10.

G17 · Know circumference of a circle = 2πr = πd and area = πr²; calculate perimeters of 2D shapes incl. circles, areas of circles and composite shapes, surface area and volume of spheres, pyramids, cones

  • For a circle, circumference is C=2πr=πdC=2\pi r=\pi d and area is A=πr2A=\pi r^2; for composite shapes, add included regions or subtract cut-out regions.
  • For a pyramid or cone, V=13×base area×perpendicular heightV=\frac13\times\text{base area}\times\text{perpendicular height}; find surface area by adding the base and every exposed triangular face, or use πrl\pi rl for a cone's curved surface.
  • For example, a sphere of radius rr has surface area 4πr24\pi r^2 and volume 43πr3\frac43\pi r^3, so doubling rr multiplies these by 44 and 88 respectively.
  • A common error is to use the diameter where a formula requires the radius, or to include an internal shared edge or face in a perimeter or surface-area total.

Tier 1 · Easy

  1. 1. A circle has diameter 13 cm13\text{ cm}. Write its circumference in terms of π\pi.[1 mark]

    Answer

    • 13π cm13\pi\text{ cm}

    Method: Use C=πdC=\pi d. With d=13 cmd=13\text{ cm}, the circumference is 13π cm13\pi\text{ cm}.

Tier 2 · Standard

  1. 1. A semicircle of diameter 10 cm10\text{ cm} is attached to one of the shorter sides of an 18 cm18\text{ cm} by 10 cm10\text{ cm} rectangle. The shared diameter is inside the shape. Work out the area and perimeter of the composite shape in terms of π\pi.[4 marks]

    Answer

    • Area =180+25π2 cm2=180+\frac{25\pi}{2}\text{ cm}^2
    • Perimeter =46+5π cm=46+5\pi\text{ cm}

    Method: The rectangle area is 18×10=180 cm218\times10=180\text{ cm}^2. The semicircle has radius 5 cm5\text{ cm}, so its area is 12π(52)=25π2 cm2\frac12\pi(5^2)=\frac{25\pi}{2}\text{ cm}^2. For the perimeter, include the two 18 cm18\text{ cm} sides, the unshared 10 cm10\text{ cm} side and the semicircular arc πr=5π cm\pi r=5\pi\text{ cm}. This gives area 180+25π2 cm2180+\frac{25\pi}{2}\text{ cm}^2 and perimeter 46+5π cm46+5\pi\text{ cm}.

Tier 3 · Hard

  1. 1. A solid cone has radius 6 cm6\text{ cm}, perpendicular height 8 cm8\text{ cm} and slant height 10 cm10\text{ cm}. Work out its total surface area, including the circular base, and its volume. Give both answers in terms of π\pi.[5 marks]

    Answer

    • Total surface area =96π cm2=96\pi\text{ cm}^2
    • Volume =96π cm3=96\pi\text{ cm}^3

    Method: The curved surface area is πrl=π(6)(10)=60π cm2\pi rl=\pi(6)(10)=60\pi\text{ cm}^2 and the base area is πr2=36π cm2\pi r^2=36\pi\text{ cm}^2, giving 96π cm296\pi\text{ cm}^2 in total. The volume is 13πr2h=13π(62)(8)=96π cm3\frac13\pi r^2h=\frac13\pi(6^2)(8)=96\pi\text{ cm}^3.

G18 · Calculate arc lengths, angles and areas of sectors of circles

  • An arc or sector is the same fraction of a circle as its central angle is of 360360^\circ.
  • Use arc length =θ360×2πr=\frac{\theta}{360}\times2\pi r and sector area =θ360×πr2=\frac{\theta}{360}\times\pi r^2, rearranging when the angle or radius is unknown.
  • For example, a 9090^\circ sector is one quarter of a circle, so its arc length is 14(2πr)\frac14(2\pi r) and its area is 14πr2\frac14\pi r^2.
  • A common error is to calculate the full circumference or area without multiplying by θ360\frac{\theta}{360}, or to include radii when only arc length is requested.

Tier 1 · Easy

  1. 1. Work out the arc length of a quarter-circle with radius 8 cm8\text{ cm}. Give the answer in terms of π\pi.[2 marks]

    Answer

    • 4π cm4\pi\text{ cm}

    Method: A quarter-circle has angle 9090^\circ. Its arc length is 90360×2π(8)=14×16π=4π cm\frac{90}{360}\times2\pi(8)=\frac14\times16\pi=4\pi\text{ cm}.

Tier 2 · Standard

  1. 1. A sector has radius 9 cm9\text{ cm} and arc length 7π cm7\pi\text{ cm}. Work out the angle of the sector and its area in terms of π\pi.[4 marks]

    Answer

    • Angle =140=140^\circ
    • Area =63π2 cm2=\frac{63\pi}{2}\text{ cm}^2

    Method: Use 7π=θ360×2π(9)7\pi=\frac{\theta}{360}\times2\pi(9). Cancelling π\pi and solving gives θ=140\theta=140^\circ. The sector area is then 140360×π(92)=63π2 cm2\frac{140}{360}\times\pi(9^2)=\frac{63\pi}{2}\text{ cm}^2.

Tier 3 · Hard

  1. 1. A shape is an annular sector with angle 144144^\circ, outer radius 12 cm12\text{ cm} and inner radius 7 cm7\text{ cm}. Work out its area and perimeter in terms of π\pi.[5 marks]

    Answer

    • Area =38π cm2=38\pi\text{ cm}^2
    • Perimeter =10+76π5 cm=10+\frac{76\pi}{5}\text{ cm}

    Method: The area is 144360π(12272)=25π(14449)=38π cm2\frac{144}{360}\pi(12^2-7^2)=\frac25\pi(144-49)=38\pi\text{ cm}^2. The two arcs have total length 25×2π(12+7)=76π5 cm\frac25\times2\pi(12+7)=\frac{76\pi}{5}\text{ cm}. The two straight radial edges each have length 127=5 cm12-7=5\text{ cm}, so the perimeter is 10+76π5 cm10+\frac{76\pi}{5}\text{ cm}.

G19 · Apply the concepts of congruence and similarity, including the relationships between lengths, areas and volumes in similar figures

  • Congruent figures have the same size and shape, while similar figures have equal corresponding angles and corresponding lengths in a constant ratio.
  • Match corresponding sides in the same order, calculate one length scale factor, and multiply or divide every corresponding length by that factor.
  • At Higher tier only, a length scale factor kk gives area scale factor k2k^2 and volume scale factor k3k^3; for example, length ratio 2:52:5 gives area ratio 4:254:25 and volume ratio 8:1258:125.
  • A common error is to compare non-corresponding sides or, at Higher tier, to use the linear scale factor directly for an area or volume.

Tier 1 · Easy

  1. 1. Triangle ABCABC has AB=5 cmAB=5\text{ cm}, AC=7 cmAC=7\text{ cm} and BAC=42\angle BAC=42^\circ. Triangle PQRPQR has PQ=5 cmPQ=5\text{ cm}, PR=7 cmPR=7\text{ cm} and QPR=42\angle QPR=42^\circ. State why the triangles are congruent.[1 mark]

    Answer

    • They are congruent by SAS.

    Method: The triangles have two pairs of equal corresponding sides, AB=PQAB=PQ and AC=PRAC=PR. The equal 4242^\circ angle is included between those sides in each triangle, so the triangles are congruent by SAS.

Tier 2 · Standard

  1. 1. Two similar shapes have corresponding lengths in the ratio smaller:larger =3:5=3:5. A side on the smaller shape is 12 cm12\text{ cm}. Another side on the larger shape is 35 cm35\text{ cm}. Work out the corresponding missing lengths.[3 marks]

    Answer

    • 12 cm12\text{ cm} corresponds to 20 cm20\text{ cm}
    • 35 cm35\text{ cm} corresponds to 21 cm21\text{ cm}

    Method: The scale factor from smaller to larger is 5/35/3. Therefore 12×53=20 cm12\times\frac53=20\text{ cm}. To reverse the enlargement, multiply by 3/53/5, giving 35×35=21 cm35\times\frac35=21\text{ cm}.

Tier 3 · Hard

  1. 1. Triangle ABCABC has side lengths 8 cm8\text{ cm}, 11 cm11\text{ cm} and 13 cm13\text{ cm}. Similar triangle DEFDEF has longest side 19.5 cm19.5\text{ cm}. Work out the other two side lengths of triangle DEFDEF and its perimeter.[4 marks]

    Answer

    • Other sides =12 cm=12\text{ cm} and 16.5 cm16.5\text{ cm}
    • Perimeter =48 cm=48\text{ cm}

    Method: The longest sides correspond, so the scale factor is 19.5/13=1.519.5/13=1.5. The other sides are 8×1.5=12 cm8\times1.5=12\text{ cm} and 11×1.5=16.5 cm11\times1.5=16.5\text{ cm}. The perimeter is 12+16.5+19.5=48 cm12+16.5+19.5=48\text{ cm}.

G20 · Know Pythagoras' theorem a² + b² = c² and the trigonometric ratios sin, cos and tan; apply them to find angles and lengths in right-angled and, where possible, general triangles in 2D and 3D figures

  • In a right-angled triangle, a2+b2=c2a^2+b^2=c^2 with cc as the hypotenuse, and sinθ=oppositehypotenuse\sin\theta=\frac{\text{opposite}}{\text{hypotenuse}}, cosθ=adjacenthypotenuse\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}, tanθ=oppositeadjacent\tan\theta=\frac{\text{opposite}}{\text{adjacent}}.
  • Label the triangle relative to the required angle, choose Pythagoras or the ratio containing the known and unknown sides, and use an inverse trigonometric function when finding an angle.
  • At Foundation tier, apply Pythagoras and trigonometry to right-angled triangles in two-dimensional figures, including those found by symmetry in isosceles triangles; at Higher tier only, extend to general (non-right) triangles and identify a right-angled cross-section before applying the same method in three dimensions.
  • A common error is to treat a non-right-angled triangle as right-angled, or to use an angle and sides that do not belong to the same right-angled cross-section.

Tier 1 · Easy

  1. 1. A right-angled triangle has perpendicular sides 6 cm6\text{ cm} and 8 cm8\text{ cm}. Work out the hypotenuse.[2 marks]

    Answer

    • 10 cm10\text{ cm}

    Method: By Pythagoras, c2=62+82=36+64=100c^2=6^2+8^2=36+64=100. Since a length is positive, c=100=10 cmc=\sqrt{100}=10\text{ cm}.

Tier 2 · Standard

  1. 1. A straight ladder of length 7.2 m7.2\text{ m} rests against a vertical wall. Its foot is 2.1 m2.1\text{ m} from the wall. Work out the height reached by the ladder and the angle it makes with the ground. Give each answer to 11 decimal place.[4 marks]

    Answer

    • Height =6.9 m=6.9\text{ m}
    • Angle =73.0=73.0^\circ

    Method: The ladder is the hypotenuse, so the height is 7.222.12=6.886 m=6.9 m\sqrt{7.2^2-2.1^2}=6.886\ldots\text{ m}=6.9\text{ m}. If the ground angle is θ\theta, then cosθ=2.1/7.2\cos\theta=2.1/7.2. Hence θ=cos1(2.1/7.2)=73.0\theta=\cos^{-1}(2.1/7.2)=73.0^\circ to 11 decimal place.

Tier 3 · Hard

  1. 1. Isosceles triangle ABCABC has AB=AC=13 cmAB=AC=13\text{ cm} and BC=10 cmBC=10\text{ cm}. Work out the perpendicular height from AA to BCBC and angle ABCABC. Give the angle to 11 decimal place.[4 marks]

    Answer

    • Height =12 cm=12\text{ cm}
    • ABC=67.4\angle ABC=67.4^\circ

    Method: The perpendicular from AA bisects the 10 cm10\text{ cm} base, giving a right-angled triangle with hypotenuse 13 cm13\text{ cm} and base 5 cm5\text{ cm}. Its height is 13252=12 cm\sqrt{13^2-5^2}=12\text{ cm}. For ABC=θ\angle ABC=\theta, tanθ=12/5\tan\theta=12/5, so θ=67.4\theta=67.4^\circ to 11 decimal place.

G21 · Know the exact values of sin θ and cos θ for θ = 0°, 30°, 45°, 60° and 90°; know the exact value of tan θ for θ = 0°, 30°, 45° and 60°

  • Know the exact sine and cosine values at 00^\circ, 3030^\circ, 4545^\circ, 6060^\circ and 9090^\circ, and the exact tangent values at 00^\circ, 3030^\circ, 4545^\circ and 6060^\circ.
  • The complete sets are sinθ:0,12,22,32,1\sin\theta:0,\frac12,\frac{\sqrt2}{2},\frac{\sqrt3}{2},1 and cosθ:1,32,22,12,0\cos\theta:1,\frac{\sqrt3}{2},\frac{\sqrt2}{2},\frac12,0 for θ=0,30,45,60,90\theta=0^\circ,30^\circ,45^\circ,60^\circ,90^\circ; also tan0=0\tan0^\circ=0, tan30=13\tan30^\circ=\frac1{\sqrt3}, tan45=1\tan45^\circ=1, tan60=3\tan60^\circ=\sqrt3.
  • For example, the 1:3:21:\sqrt3:2 triangle gives sin30=12\sin30^\circ=\frac12, cos30=32\cos30^\circ=\frac{\sqrt3}{2} and tan30=13\tan30^\circ=\frac1{\sqrt3}.
  • A common error is to give a decimal approximation when an exact value is required, or to interchange the opposite and adjacent sides for 3030^\circ and 6060^\circ.

Tier 1 · Easy

  1. 1. Work out the exact value of sin30+cos60\sin30^\circ+\cos60^\circ.[1 mark]

    Answer

    • 11

    Method: sin30=12\sin30^\circ=\frac12 and cos60=12\cos60^\circ=\frac12. Therefore the sum is 12+12=1\frac12+\frac12=1.

Tier 2 · Standard

  1. 1. Work out the exact value of 2sin45cos45+cos602\sin45^\circ\cos45^\circ+\cos60^\circ.[3 marks]

    Answer

    • 32\frac32

    Method: sin45=cos45=22\sin45^\circ=\cos45^\circ=\frac{\sqrt2}{2} and cos60=12\cos60^\circ=\frac12. Therefore 2sin45cos45+cos60=2(22)(22)+12=1+12=322\sin45^\circ\cos45^\circ+\cos60^\circ=2(\frac{\sqrt2}{2})(\frac{\sqrt2}{2})+\frac12=1+\frac12=\frac32.

Tier 3 · Hard

  1. 1. The hypotenuse of a right-angled triangle is 12 cm12\text{ cm} and one acute angle is 3030^\circ. Work out its exact area.[4 marks]

    Answer

    • 183 cm218\sqrt3\text{ cm}^2

    Method: The side opposite 3030^\circ is 12sin30=12×12=6 cm12\sin30^\circ=12\times\frac12=6\text{ cm}. The adjacent side is 12cos30=12×32=63 cm12\cos30^\circ=12\times\frac{\sqrt3}{2}=6\sqrt3\text{ cm}. Hence the area is 12×6×63=183 cm2\frac12\times6\times6\sqrt3=18\sqrt3\text{ cm}^2.

G22 · Know and apply the sine rule a/sin A = b/sin B = c/sin C, and cosine rule a² = b² + c² - 2bc cos A, to find unknown lengths and angles [Higher only]

  • The sine rule asinA=bsinB=csinC\frac{a}{\sin A}=\frac{b}{\sin B}=\frac{c}{\sin C} pairs each side with its opposite angle, while the cosine rule connects three sides with one angle.
  • Use the sine rule when an opposite side-angle pair is known; use the cosine rule for two sides and their included angle or for all three sides.
  • When the sine rule gives sinB=k\sin B=k, check both B=sin1kB=\sin^{-1}k and B=180sin1kB=180^\circ-\sin^{-1}k against the triangle angle sum.
  • A common error is to pair a side with a non-opposite angle or to ignore the second possible angle in an ambiguous sine-rule problem.

Tier 1 · Easy

  1. 1. In triangle ABCABC, side a=7 cma=7\text{ cm}, angle A=30A=30^\circ and angle B=90B=90^\circ. Work out side bb.[2 marks]

    Answer

    • 14 cm14\text{ cm}

    Method: By the sine rule, bsin90=7sin30\frac{b}{\sin90^\circ}=\frac{7}{\sin30^\circ}. Hence b=7×11/2=14 cmb=7\times\frac{1}{1/2}=14\text{ cm}.

Tier 2 · Standard

  1. 1. Two sides of a triangle are 7 cm7\text{ cm} and 10 cm10\text{ cm}, and the included angle is 6060^\circ. Work out the exact length of the third side.[3 marks]

    Answer

    • 79 cm\sqrt{79}\text{ cm}

    Method: Using the cosine rule, c2=72+1022(7)(10)cos60=49+10070=79c^2=7^2+10^2-2(7)(10)\cos60^\circ=49+100-70=79. Therefore c=79 cmc=\sqrt{79}\text{ cm}.

Tier 3 · Hard

  1. 1. In triangle ABCABC, A=35A=35^\circ, a=8 cma=8\text{ cm} and b=11 cmb=11\text{ cm}. Find all possible values of angles BB and CC. Give each angle to 11 decimal place.[5 marks]

    Answer

    • B=52.1B=52.1^\circ, C=92.9C=92.9^\circ
    • B=127.9B=127.9^\circ, C=17.1C=17.1^\circ

    Method: The sine rule gives sinB=11sin358=0.7887\sin B=\frac{11\sin35^\circ}{8}=0.7887\ldots. Therefore B=52.1B=52.1^\circ or B=18052.1=127.9B=180^\circ-52.1^\circ=127.9^\circ. The corresponding third angles are C=1803552.1=92.9C=180^\circ-35^\circ-52.1^\circ=92.9^\circ and C=18035127.9=17.1C=180^\circ-35^\circ-127.9^\circ=17.1^\circ.

G23 · Know and apply Area = ½ ab sin C to calculate the area, sides or angles of any triangle [Higher only]

  • The area of a triangle is A=12absinCA=\frac12ab\sin C, where CC is the included angle between sides aa and bb.
  • Substitute the two sides and their included angle to find area, or rearrange before using an inverse sine to find an angle.
  • If sinC=k\sin C=k, both C=sin1kC=\sin^{-1}k and C=180sin1kC=180^\circ-\sin^{-1}k may give triangles with the same area.
  • A common error is to use an angle that is not between the two substituted sides, or to reject an obtuse solution without checking the information given.

Tier 1 · Easy

  1. 1. Two sides of a triangle are 10 cm10\text{ cm} and 7 cm7\text{ cm}, and their included angle is 3030^\circ. Work out the area.[2 marks]

    Answer

    • 17.5 cm217.5\text{ cm}^2

    Method: A=12absinC=12(10)(7)sin30=35×12=17.5 cm2A=\frac12ab\sin C=\frac12(10)(7)\sin30^\circ=35\times\frac12=17.5\text{ cm}^2.

Tier 2 · Standard

  1. 1. A triangle has area 48 cm248\text{ cm}^2. Two sides have lengths 12 cm12\text{ cm} and x cmx\text{ cm}, and their included angle is 3030^\circ. Work out xx.[3 marks]

    Answer

    • x=16x=16

    Method: Use 48=12(12)(x)sin3048=\frac12(12)(x)\sin30^\circ. Since sin30=12\sin30^\circ=\frac12, this becomes 48=3x48=3x. Therefore x=16x=16.

Tier 3 · Hard

  1. 1. Two sides of a triangle are 10 cm10\text{ cm} and 12 cm12\text{ cm}. Its area is 303 cm230\sqrt3\text{ cm}^2. Find both possible values of the included angle.[4 marks]

    Answer

    • 6060^\circ or 120120^\circ

    Method: 303=12(10)(12)sinC=60sinC30\sqrt3=\frac12(10)(12)\sin C=60\sin C, so sinC=32\sin C=\frac{\sqrt3}{2}. Between 00^\circ and 180180^\circ, this occurs at C=60C=60^\circ and C=120C=120^\circ.

G24 · Describe translations as 2D vectors

  • A translation moves every point through the same horizontal and vertical displacement without changing the shape's size or orientation.
  • Describe a translation by the column vector (xy)\binom{x}{y}, where positive xx is right, negative xx is left, positive yy is up and negative yy is down.
  • For example, moving 44 units left and 33 units up is the translation vector (43)\binom{-4}{3}.
  • A common error is to reverse the vector by subtracting the image coordinates from the object coordinates instead of calculating image minus object.

Tier 1 · Easy

  1. 1. Point A=(3,4)A=(-3,4) is translated to A=(2,1)A'=(2,-1). Describe the translation as a vector.[2 marks]

    Answer

    • (55)\binom{5}{-5}

    Method: Calculate image minus object in each coordinate: 2(3)=52-(-3)=5 and 14=5-1-4=-5. The translation vector is (55)\binom{5}{-5}.

Tier 2 · Standard

  1. 1. Triangle ABCABC has vertices A=(1,2)A=(1,-2), B=(5,1)B=(5,1) and C=(2,4)C=(2,4). It is translated by (43)\binom{-4}{3}. Write the coordinates of the three image vertices.[3 marks]

    Answer

    • A=(3,1)A'=(-3,1)
    • B=(1,4)B'=(1,4)
    • C=(2,7)C'=(-2,7)

    Method: Add 4-4 to every xx-coordinate and 33 to every yy-coordinate. This gives A=(3,1)A'=(-3,1), B=(1,4)B'=(1,4) and C=(2,7)C'=(-2,7).

Tier 3 · Hard

  1. 1. A translation maps P=(6,4)P=(-6,4) to P=(1,2)P'=(1,-2). The same translation maps Q=(3,k)Q=(3,k) to Q=(10,5)Q'=(10,5). Find kk and describe the translation as a vector.[4 marks]

    Answer

    • k=11k=11
    • (76)\binom{7}{-6}

    Method: From PP to PP', the displacement is 1(6)=71-(-6)=7 horizontally and 24=6-2-4=-6 vertically, so the vector is (76)\binom{7}{-6}. Therefore the image of Q=(3,k)Q=(3,k) has yy-coordinate k6k-6. Since k6=5k-6=5, k=11k=11.

G25 · Apply addition and subtraction of vectors, multiplication of vectors by a scalar, and diagrammatic and column representations of vectors; use vectors to construct geometric arguments and proofs

  • Vectors have magnitude and direction; they can be represented by directed line segments, column vectors or algebraic symbols such as a\mathbf{a} and b\mathbf{b}.
  • Add vectors component by component, subtract to reverse a displacement, and multiply by a scalar to change magnitude and, for a negative scalar, direction.
  • For a route through successive points, add vectors in travel order; at Higher tier only, compare two vector routes or show one direction vector is a scalar multiple of another to construct a geometric proof.
  • A common error is to subtract vectors in the wrong order or to forget that multiplying by a negative scalar reverses the vector's direction.

Tier 1 · Easy

  1. 1. Work out (35)+(72)\binom{3}{-5}+\binom{-7}{2}.[1 mark]

    Answer

    • (43)\binom{-4}{-3}

    Method: Add corresponding components: 3+(7)=43+(-7)=-4 and 5+2=3-5+2=-3. Therefore the sum is (43)\binom{-4}{-3}.

Tier 2 · Standard

  1. 1. Points AA and BB have position vectors a=(21)\mathbf{a}=\binom{2}{-1} and b=(85)\mathbf{b}=\binom{8}{5}. Point MM is the midpoint of ABAB. Find the position vector of MM and the vector AM\overrightarrow{AM}.[3 marks]

    Answer

    • OM=(52)\overrightarrow{OM}=\binom{5}{2}
    • AM=(33)\overrightarrow{AM}=\binom{3}{3}

    Method: The midpoint position vector is 12(a+b)=12(104)=(52)\frac12(\mathbf{a}+\mathbf{b})=\frac12\binom{10}{4}=\binom{5}{2}. Then AM=OMOA=(52)(21)=(33)\overrightarrow{AM}=\overrightarrow{OM}-\overrightarrow{OA}=\binom{5}{2}-\binom{2}{-1}=\binom{3}{3}.

Tier 3 · Hard

  1. 1. A walker starts at P=(3,2)P=(-3,2). The walker makes successive displacements (43)\binom{4}{3}, (15)\binom{-1}{5} and 2(12)-2\binom{1}{-2}. Work out the resultant displacement, the walker's finishing coordinates and the vector that would take the walker directly back to PP.[4 marks]

    Answer

    • Resultant =(112)=\binom{1}{12}
    • Finish =(2,14)=(-2,14)
    • Return vector =(112)=\binom{-1}{-12}

    Method: First, 2(12)=(24)-2\binom{1}{-2}=\binom{-2}{4}. Adding all displacements gives (43)+(15)+(24)=(112)\binom{4}{3}+\binom{-1}{5}+\binom{-2}{4}=\binom{1}{12}. Add this to P=(3,2)P=(-3,2) to get the finish (2,14)(-2,14). The return vector is the negative of the resultant, (112)\binom{-1}{-12}.