Edexcel International GCSE Mathematics A · 4MA1
Transformations
A complete transformation description specifies the transformation and all parameters needed to reproduce it. Translations need a vector; reflections need a mirror line; rotations need a centre, angle and direction; enlargements need a centre and scale factor.
Key method
For enlargement about the origin, multiply both coordinates by the scale factor. For another centre, scale the displacement from that centre instead.
Worked example
Enlarge A(3, 2) by scale factor 2 about centre C(1, 1).
- Find the displacement from C to A: (3 − 1, 2 − 1) = (2, 1).
- Double that displacement to (4, 2).
- Add it to the centre: (1, 1) + (4, 2).
Answer and interpretation
A′ = (5, 3).
Common mistake
Multiplying the original coordinates by 2 enlarges about the origin, not the stated centre.
Practise independently
Reflect (4, −2) in the line y = x.
Check your answer
The coordinates swap, giving (−2, 4).
Syllabus connection
This lesson develops enlargements within the geometry area. Start with the worked method, attempt the independent question without looking at its answer, then explain any correction in your own words. Check the official specification for your tier’s full requirements.
Related resources
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