What is important to know about Transformations (RREST)?

Translation: described by a column vector (x, y) — x is right/left, y is up/down.

What is important to know about Transformations (RREST)?

Reflection: described by the mirror line (e.g. y = x, x = 2).

What is important to know about Transformations (RREST)?

Rotation: described by the centre, angle, and direction (clockwise/anticlockwise).

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Geometry & Measures · Foundation & Higher

Transformations (RREST)

Q: What are common mistakes with Transformations (RREST)?

Not fully describing a transformation — missing the mirror line, centre of rotation, or scale factor.

Q: What are common mistakes with Transformations (RREST)?

Using scale factor incorrectly in enlargement: multiplying coordinates by SF from the wrong origin.

Q: What exam tips are there for Transformations (RREST)?

Always give a full description: rotation needs centre + angle + direction; enlargement needs centre + scale factor.

Q: What exam tips are there for Transformations (RREST)?

Tracing paper is very helpful for rotations — ask for it in exams if not provided.

The four transformations are Rotation, Reflection, Enlargement and Translation (RREST). Each moves or resizes a shape in a specific way, and you must describe them fully.

Revising transformations (rrest) the night before an exam? These are condensed revision notes — the facts, formulas and mistakes examiners actually mark, with no long explanations. Prefer a full walkthrough with step-by-step reasoning instead? Search “Transformations (RREST) GCSE” on the site for the complete guide.

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Key facts to remember

1Translation: described by a column vector (x, y) — x is right/left, y is up/down.
2Reflection: described by the mirror line (e.g. y = x, x = 2).
3Rotation: described by the centre, angle, and direction (clockwise/anticlockwise).
4Enlargement: described by the centre of enlargement and scale factor. Scale factor > 1 enlarges, 0 < SF < 1 reduces.
5After a translation, reflection or rotation, the shape is congruent to the original (same size and shape).
6Enlargement changes size but preserves angles.

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Worked examples

Example 1

Describe fully the transformation that maps shape A to shape B, where B is the mirror image of A in the line y = −1.

Working

The shapes are congruent and mirror images → reflection
Identify the mirror line between corresponding points → y = −1
Transformation: Reflection in the line y = −1

AnswerReflection in the line y = −1

Example 2

Enlarge triangle with vertices (1,1), (3,1), (1,3) by scale factor 2, centre (0,0).

Working

Multiply each coordinate by the scale factor 2
(1,1) → (2,2)
(3,1) → (6,2)
(1,3) → (2,6)

AnswerNew vertices: (2,2), (6,2), (2,6)

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Common mistakes

✗Not fully describing a transformation — missing the mirror line, centre of rotation, or scale factor.

✗Using scale factor incorrectly in enlargement: multiplying coordinates by SF from the wrong origin.

✗Confusing rotation direction (clockwise vs anticlockwise).

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Exam tips

✓Always give a full description: rotation needs centre + angle + direction; enlargement needs centre + scale factor.

✓Tracing paper is very helpful for rotations — ask for it in exams if not provided.

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