Transformations: reflection, rotation, translation, enlargement
Describe and carry out the four transformations on a coordinate grid, including the details examiners expect, with worked examples.
GCSEHigh SchoolCurriculum fit: GCSE Maths Geometry and measures (Foundation and Higher; negative scale factors are Higher). US: Geometry (Congruence).
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What is it?
A transformation changes the position or size of a shape. Translations, reflections and rotations keep the shape the same size (the image is congruent to the original). Enlargements change the size (the image is similar).
To describe a transformation fully, you must give all the details: for a rotation, for example, the angle, direction and centre.
Key formulas and ideas
- Translation: described by a vector (x, y), where x is the move right and y is the move up.
- Reflection: described by the mirror line, such as x = 2 or y = x.
- Rotation: angle, direction (clockwise or anticlockwise) and centre. A 90° anticlockwise rotation about the origin maps (x, y) to (−y, x).
- Enlargement: scale factor and centre of enlargement.
Worked examples
Example 1: Translation
Question: Translate the point (2, 3) by the vector (4, −1).
- Add the x movement: 2 + 4 = 6.
- Add the y movement: 3 − 1 = 2.
Answer: (6, 2)
Example 2: Reflection
Question: Reflect (3, 1) in the y-axis.
- The y-axis is the line x = 0.
- The x-coordinate changes sign and y stays the same.
Answer: (−3, 1)
Example 3: Rotation
Question: Rotate (2, 1) by 90° anticlockwise about the origin.
- Use the rule (x, y) → (−y, x).
- (2, 1) → (−1, 2).
Answer: (−1, 2)
Common mistakes
- Describing a transformation with only the name, such as 'rotation', and missing the angle or centre.
- Confusing clockwise and anticlockwise.
- Reflecting the wrong distance from the mirror line.
- Applying a scale factor from the wrong centre.
Practice questions
Frequently asked questions
What is the centre of enlargement?
The fixed point from which the shape is enlarged. Distances from this point are multiplied by the scale factor.
Which transformations keep the shape congruent?
Translations, reflections and rotations. Enlargements do not.
Related guides
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GCSEHigh SchoolSources and review
- DfE: GCSE mathematics subject content and assessment objectives
- Common Core State Standards: Mathematics (high school)
Reviewed by StudyMorrow editorial review on 5 Nov 2026.