Skip to content
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)

Transformations

Worked answers, methods and verified real exam appearances for G7 on Edexcel GCSE Maths 1MA1.

Explanation

  • Describe a transformation completely: a translation needs a column vector; a rotation needs centre, angle and direction; a reflection needs its mirror line; an enlargement needs centre and scale factor. Translation, rotation and reflection preserve every length and angle, so object and image are congruent.
  • Enlargement preserves angles and multiplies every length from the centre by the scale factor. For centre CC, use CP=kCP\overrightarrow{CP'}=k\overrightarrow{CP}.
  • A fractional factor shrinks the shape.
  • At Higher tier, a negative factor also puts every image point on the opposite side of the centre.
  • Examiners require every defining detail, not just the transformation name.
Corresponding points lie the same perpendicular distance from a reflection line.

Worked example

Point P(5,1)P(5,1) is enlarged by scale factor 22 about centre C(2,3)C(2,3). Find PP'.

  1. 1.CP=(52,13)=(3,2)\overrightarrow{CP}=(5-2,1-3)=(3,-2).
  2. 2.Multiply by 22: CP=(6,4)\overrightarrow{CP'}=(6,-4).
  3. 3.Add the centre: P=(2+6,34)=(8,1)P'=(2+6,3-4)=(8,-1).

Answer: P=(8,1)P'=(8,-1).

Common mistakes

  • Don't give 'rotation' without its centre, angle and direction, or 'reflection' without the mirror line.
  • Don't multiply the original coordinates by the scale factor even though the enlargement centre is not the origin.

Exam tip

For an enlargement, draw straight rays from the centre through corresponding points to check the centre and scale factor.

Worked practice

Q1
Tier 1 · Easy

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)

(Total for Question 1 is 2 marks)

Mark scheme

Mark scheme for question 1
QuestionAnswerMarkMark scheme
1
  • (2,2)(2,2)
2Add the vector components to the coordinates: (3+5,42)=(2,2)(-3+5,4-2)=(2,2).
Q2
Tier 2 · Standard

2

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

(2)

(Total for Question 2 is 2 marks)

Mark scheme

Mark scheme for question 2
QuestionAnswerMarkMark scheme
2
  • P(1,4)P'(1,4)
2A 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).
Q3
Tier 3 · Hard

3

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)

(Total for Question 3 is 4 marks)

Mark scheme

Mark scheme for question 3
QuestionAnswerMarkMark scheme
3
  • A(0,3)A'(0,-3)
  • B(3,4)B'(3,-4)
  • C(4,1)C'(4,-1)
4Subtract 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).
Q4
Tier 1 · Easy

4

Point B(4,3)B(-4,3) is reflected in the yy-axis. Write down the coordinates of its image.

(1)

(Total for Question 4 is 1 mark)

Mark scheme

Mark scheme for question 4
QuestionAnswerMarkMark scheme
4
  • (4,3)(4,3)
1Reflection in the yy-axis changes the sign of the xx-coordinate and keeps the yy-coordinate, so (4,3)(-4,3) maps to (4,3)(4,3).
Q5
Tier 2 · Standard

5

Point C(5,2)C(5,-2) is enlarged by scale factor 33 about the origin. Find the coordinates of its image.

(2)

(Total for Question 5 is 2 marks)

Mark scheme

Mark scheme for question 5
QuestionAnswerMarkMark scheme
5
  • (15,6)(15,-6)
2For an enlargement about the origin, multiply both coordinates by the scale factor: (5×3,2×3)=(15,6)(5\times3,-2\times3)=(15,-6).
Q6
Tier 3 · Hard

6

Describe fully the single transformation that maps the triangle with vertices (3,1)(3,1), (6,1)(6,1) and (3,4)(3,4) to the triangle with vertices (1,5)(1,5), (1,8)(1,8) and (2,5)(-2,5).

(3)

(Total for Question 6 is 3 marks)

Mark scheme

Mark scheme for question 6
QuestionAnswerMarkMark scheme
6
  • Rotation 9090^\circ anticlockwise about (0,2)(0,2) (accept rotation 270270^\circ clockwise about (0,2)(0,2))
3Relative to the centre (0,2)(0,2), each vertex is rotated a quarter turn anticlockwise: the rule is (x,y)(2y,x+2)(x,y)\mapsto(2-y,\,x+2), so (3,1)(1,5)(3,1)\mapsto(1,5), (6,1)(1,8)(6,1)\mapsto(1,8) and (3,4)(2,5)(3,4)\mapsto(-2,5). Both triangles have the same orientation, so the transformation is a rotation; the centre (0,2)(0,2) is the fixed point of the vertex correspondences.
Q7
Tier 2 · Standard

7

Triangle ABCABC has vertices A(3,2)A(-3,2), B(1,5)B(1,5) and C(4,2)C(4,-2). The triangle is reflected in the line y=xy=x. Find the coordinates of the three image vertices.

(2)

(Total for Question 7 is 2 marks)

Mark scheme

Mark scheme for question 7
QuestionAnswerMarkMark scheme
7
  • A(2,3)A'(2,-3)
  • B(5,1)B'(5,1)
  • C(2,4)C'(-2,4)
2Reflection in y=xy=x swaps each point's coordinates. Therefore (3,2)(2,3)(-3,2)\mapsto(2,-3), (1,5)(5,1)(1,5)\mapsto(5,1) and (4,2)(2,4)(4,-2)\mapsto(-2,4).
Q8
Tier 3 · Hard

8

An enlargement maps A(2,1)A(2,1) to A(5,3)A'(5,3) and B(8,1)B(8,1) to B(8,3)B'(8,3). Describe the enlargement fully.

(4)

(Total for Question 8 is 4 marks)

Mark scheme

Mark scheme for question 8
QuestionAnswerMarkMark scheme
8
  • Enlargement with centre (8,5)(8,5) and scale factor 12\frac12
4The object length ABAB is 66 and the image length ABA'B' is 33, so the scale factor is 12\frac12. The centre lies on both AAAA' and BBBB'. Line BBBB' is x=8x=8; extending AAAA' to meet it gives (8,5)(8,5). Equivalently, for scale factor 12\frac12, the centre is 2AA=(8,5)2A'-A=(8,5).
Q9
Tier 3 · Hard

9

A translation maps A(4,3)A(-4,3) to A(2,2)A'(2,-2). Describe the translation fully. The same translation maps B(1,4)B(1,4) to BB', C(3,2)C(-3,-2) to CC', and DD to D(0,6)D'(0,6). Work out the coordinates of BB', CC' and DD.

(4)

(Total for Question 9 is 4 marks)

Mark scheme

Mark scheme for question 9
QuestionAnswerMarkMark scheme
9
  • Translation by (65)\begin{pmatrix}6\\-5\end{pmatrix}; B=(7,1)B'=(7,-1); C=(3,7)C'=(3,-7); D=(6,11)D=(-6,11)
4The movement from AA to AA' is (2(4),23)=(6,5)(2-(-4),-2-3)=(6,-5), so the translation vector is (65)\begin{pmatrix}6\\-5\end{pmatrix}. Adding it gives B=(1+6,45)=(7,1)B'=(1+6,4-5)=(7,-1) and C=(3+6,25)=(3,7)C'=(-3+6,-2-5)=(3,-7). Subtracting the vector from DD' gives D=(06,6(5))=(6,11)D=(0-6,6-(-5))=(-6,11).
Q10
Tier 3 · Hard

10

Higher only: An enlargement with scale factor 2-2 maps P(4,1)P(4,1) to P(5,7)P'(-5,7). Work out the centre of enlargement. The same enlargement maps Q(2,5)Q(-2,5) to QQ'. Work out the coordinates of QQ'.

(4)

(Total for Question 10 is 4 marks)

Mark scheme

Mark scheme for question 10
QuestionAnswerMarkMark scheme
10
  • Centre (1,3)(1,3); Q=(7,1)Q'=(7,-1)
4For centre CC, the rule is P=C2(PC)=3C2PP'=C-2(P-C)=3C-2P. Hence 3C=P+2P=(5,7)+(8,2)=(3,9)3C=P'+2P=(-5,7)+(8,2)=(3,9), so C=(1,3)C=(1,3). From CC to QQ the vector is (3,2)(-3,2). Multiplying it by 2-2 gives (6,4)(6,-4), and adding this to CC gives Q=(7,1)Q'=(7,-1).

Verified exam appearances

SeriesPaperQuestionMarksCalculatorTierLinks
2024-061HQ113Non-calculatorHigherQPMS
2022-061FQ31Non-calculatorFoundationQPMS
2022-113FQ182AllowedFoundationQPMS
2024-112HQ112AllowedHigherQPMS
2024-061FQ192Non-calculatorFoundationQPMS
2023-112FQ212AllowedFoundationQPMS
2023-063FQ162AllowedFoundationQPMS
2024-063FQ183AllowedFoundationQPMS
2023-111FQ112Non-calculatorFoundationQPMS
2022-111HQ112Non-calculatorHigherQPMS
2022-111FQ114Non-calculatorFoundationQPMS
2024-111FQ103Non-calculatorFoundationQPMS
2019-063HQ82AllowedHigherQPMS
2022-062FQ222AllowedFoundationQPMS
2019-113HQ92AllowedHigherQPMS
2022-062HQ132AllowedHigherQPMS
2022-062HQ22AllowedHigherQPMS
2019-061FQ263Non-calculatorFoundationQPMS
2021-112FQ112AllowedFoundationQPMS
2023-062FQ122AllowedFoundationQPMS
2019-112FQ132AllowedFoundationQPMS
2024-063HQ122AllowedHigherQPMS
2021-113FQ162AllowedFoundationQPMS
2019-113FQ182AllowedFoundationQPMS
2019-061HQ53Non-calculatorHigherQPMS
2024-112FQ182AllowedFoundationQPMS

Other points in G Geometry and measures

Want help turning this into marks?

Bring G7 or any tricky specification point, and we can work through the method and exam wording together.