Four transformations: translation, reflection, rotation, enlargement. State all required parts in descriptions or lose marks.
What you’ll learn
Mapped to the Pearson Edexcel IGCSE 4MA1 syllabus (2026 onwards).
5.2 — Translate a shape by a column vector.
5.2 — Reflect a shape in a horizontal, vertical, or diagonal line.
5.2 — Rotate a shape about a given centre, angle and direction.
5.2 — Enlarge a shape (positive, negative, fractional scale factors).
5.2 — Describe a transformation FULLY, stating ALL required information.
Translation
Move every point by the same vector.
Translation moves every point of a shape by the same column vector (yx).
Shape and size: UNCHANGED.
Orientation: UNCHANGED.
Image is congruent to original.
Worked example. Translate the point (3,5) by (−24).
(3+4,5+(−2))=(7,3).
Describing. "Translation by vector (−24)." That's it — one line.
Edexcel tip. Express the vector as a COLUMN, not as words. "4 right and 2 down" = 0 marks. (−24) = 1 mark.
Add vector to every coordinate.
Shape and orientation unchanged.
Describe with column vector.
Image is congruent.
Reflection
Flip over a mirror line. Orientation reversed.
Reflection flips the shape over a mirror line.
Shape and size: UNCHANGED.
Orientation: REVERSED (mirror image).
Points on the mirror line are INVARIANT.
Common mirror lines and rules:
Mirror line
Effect on (x,y)
x-axis (y=0)
(x,−y)
y-axis (x=0)
(−x,y)
y=x
(y,x) — swap
y=−x
(−y,−x) — swap and negate
Worked example. Reflect (4,1) in y=x. Swap: (1,4).
Worked example. Reflect (3,5) in y-axis. Negate x: (−3,5).
Reflection flips the shape; each point keeps its distance from the mirror line, on the opposite side.
Reflection in x=a or y=a. Distance from line is preserved on the other side.
Describing. "Reflection in the line y=−x." State the equation of the line.
Edexcel tip. If the mirror is at x=2 and the point is at (5,3), the image is at (2−(5−2),3)=(−1,3) — i.e., move the same distance the OTHER way.
Flip over mirror line.
Orientation reversed.
Memorise the four common rules.
Describe with line equation.
Rotation
Turn about a centre. Three pieces of info.
Rotation turns the shape about a fixed centre by a given angle and direction.
Shape and size: UNCHANGED.
Orientation: PRESERVED (not reversed).
Centre is INVARIANT.
About the origin(0,0):
Angle + direction
Effect on (x,y)
90° anticlockwise
(−y,x)
90° clockwise
(y,−x)
180° (either way)
(−x,−y)
270° anticlockwise
(y,−x) — same as 90° clockwise
Worked example. Rotate (3,2) by 90° clockwise about origin. (2,−3).
Worked example. Rotate (3,2) by 180° about origin. (−3,−2).
About a non-origin centre. Use tracing paper. Or:
Translate centre to origin.
Rotate.
Translate back.
Describing. "Rotation by 90° anticlockwise about (0,0)." State ALL THREE: angle, direction, centre.
Edexcel tip. Tracing paper is allowed (and useful). Trace the original shape + centre. Pin at centre. Rotate the paper. Mark image positions.
Three things: angle, direction, centre.
Origin rules: memorise.
Use tracing paper.
Orientation preserved.
Enlargement (including negative and fractional)
Scale from a centre. Negative flips. Fractional shrinks.
Enlargement scales the shape from a centre point by a scale factor k.
∣k∣>1: image is bigger.
∣k∣<1: image is smaller.
k>0: same side of centre.
k<0: OPPOSITE side of centre.
About the origin. Multiply each coordinate by k.
Worked example. Enlarge (4,2) by scale factor 2 from origin: (8,4).
Worked example. Enlarge (4,2) by scale factor −2 from origin. Multiply by −2: (−8,−4). Note image is in the OPPOSITE quadrant.
A negative scale factor enlarges through the centre: the image is bigger and on the opposite side.
Worked example. Enlarge (4,2) by scale factor 21 from origin: (2,1). Image is HALF the size.
About a non-origin centre (cx,cy).x′=cx+k(x−cx),y′=cy+k(y−cy)
I.e., translate centre to origin, scale, translate back.
Describing. "Enlargement, scale factor −2, centre (0,0)." State BOTH scale factor AND centre.
Edexcel tip. Negative scale factor catches many students. The image is ROTATED 180° AS WELL as scaled — it's NOT just on a different side; it's flipped.
Scale factor + centre.
∣k∣>1 bigger; ∣k∣<1 smaller.
k<0 flips through centre.
Multiply coords by k (when centre is origin).
Describing transformations FULLY
Mark schemes give 0 for partial. State everything.
Identify the type, then state ALL required information:
Transformation
Required info
Translation
Vector (yx)
Reflection
Equation of the mirror line
Rotation
Angle + direction (cw/acw) + centre
Enlargement
Scale factor + centre
How to identify.
Same orientation, same size, just shifted: TRANSLATION.
Mirror image (flipped): REFLECTION.
Same orientation but turned: ROTATION.
Different size: ENLARGEMENT.
Worked example. Triangle A at (2,1),(4,1),(4,3) maps to A′ at (2,−1),(4,−1),(4,−3).
Combining transformations. Some questions ask for a single transformation equivalent to a sequence. Trace the image step by step, then describe the net effect.
Edexcel tip. Common errors flagged in examiner reports:
"Translation 4 to the right" — must use vector form (04).
"Reflection in y" — must give equation y=? or "the y-axis".
"Rotation 90°" — must state direction and centre.
"Enlargement scale factor 2" — must state centre.
Identify the type first.
List ALL required pieces.
Use precise language: 'vector', 'mirror line', 'centre'.
Sketch if uncertain.
How it’s examined
Both papers feature transformations. Common formats: (a) perform a transformation on a grid; (b) describe a single transformation given before/after. Negative scale factors and rotations with non-origin centres trip students. Tracing paper is allowed.
Worked examples, formulae, definitions and the mistakes examiners flag — everything you need to push from a pass to an A*.
Take this whole topic with you
Download a branded revision sheet — worked examples, formulae, definitions and common mistakes for Transformation Geometry , ready to print or save as PDF.
Step-by-step worked examples — Transformation Geometry
Step-by-step solutions to past-paper-style questions on transformation geometry , written exactly the way a tutor would explain them at the board.
1Translation by a vector
Foundation• translation
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Question
Translate the point (3,5) by (−24).
Step-by-step solution
Step 1
Add the translation vector to the point's coordinates.
Enlarge (4,2) by scale factor −2 from centre origin.
Step-by-step solution
Step 1
Multiply by negative scale factor. Image lands on the OPPOSITE side of the centre.
Step 2
(4×−2,2×−2)=(−8,−4).
Answer
(−8,−4)
Examiner tip
Negative scale factor: image is enlarged AND on the opposite side of centre. Often confused — check the quadrant.
6Describing a transformation
Higher• Adapted from 4MA1/1H Jan 2024 Q19• describe
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Question
Triangle A at (2,1),(4,1),(4,3) maps to A′ at (2,−1),(4,−1),(4,−3). Describe fully.
Step-by-step solution
Step 1
y-coordinate flipped sign — reflection in the x-axis.
Step 2
Description: reflection in the line y=0 (the x-axis).
Answer
Reflection in the line y=0 (x-axis).
Examiner tip
TRANSLATION: state vector. REFLECTION: state mirror line. ROTATION: state angle, direction, centre. ENLARGEMENT: state scale factor and centre. Mark scheme awards 0 for partial descriptions.
Key Definitions and Keywords — Transformation Geometry
Definitions to memorise and the exact keywords mark schemes credit for transformation geometry answers — sharpened from recent examiner reports for the 2026 Pearson Edexcel IGCSE 4MA1 sitting.
Translation
Examiner keyword
A transformation that moves every point by the same vector. Shape and size unchanged.
Reflection
Examiner keyword
A transformation that flips the shape over a mirror line. Shape and size unchanged; orientation reversed.
Rotation
Examiner keyword
A transformation that turns the shape about a fixed centre by a given angle and direction. Shape and size unchanged.
Enlargement
Examiner keyword
A transformation that scales the shape from a centre point by a scale factor. Size changes; shape (angles) preserved.
Scale factor
Ratio of new length to original length. ∣k∣>1 enlarges, ∣k∣<1 shrinks. Negative k flips through the centre.
Invariant point
A point that does not move under a transformation. The centre of rotation/enlargement is invariant; points on a mirror line are invariant.
Common Mistakes and Misconceptions — Transformation Geometry
The traps other students keep falling into on transformation geometry questions — taken from recent Pearson Edexcel IGCSE 4MA1 examiner reports and mark schemes — and how to avoid them.
✕Incomplete description (missing centre, vector, etc.)
4MA1 — examiner reports 2022-2024
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Why it happens
Forgetting all the required parts.
How to avoid it
Translation: VECTOR. Reflection: MIRROR LINE. Rotation: ANGLE + DIRECTION + CENTRE. Enlargement: SCALE FACTOR + CENTRE. Mark schemes give 0 for partial.
✕Confusing clockwise vs anticlockwise rotation
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Why it happens
90° rotation has two possibilities.
How to avoid it
90° anticlockwise: (x,y)→(−y,x). 90° clockwise: (x,y)→(y,−x). Sketch a quick diagram to check.
✕Negative scale factor not flipping through centre
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Why it happens
Treating it as a positive enlargement.
How to avoid it
Negative scale factor: image is on the OPPOSITE side of the centre. Distance from centre increases by factor ∣k∣.
✕Fractional scale factor giving a larger shape
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Why it happens
Forgetting that ∣k∣<1 means smaller.
How to avoid it
k=1/2: image is HALF the size. k=2: image is TWICE.
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