Key Terms
- Translation: Sliding a shape — position changes, everything else stays same
- Reflection: Flipping a shape over a mirror line
- Rotation: Turning a shape around a fixed centre point
- Enlargement: Scaling a shape from a centre point — the ONLY one that changes size
- Object: The original shape; Image: The result after transformation
Must-Know Facts
- Translation: state the column vector
- Reflection: state the mirror line equation
- Rotation: state centre, angle, and direction (CW or ACW)
- Enlargement: state centre and scale factor
- Only enlargement changes the SIZE of the shape
- Never say just "rotation" — always give all required details
Key Methods
- Size changed? → Enlargement
- Flipped/mirrored? → Reflection
- Same size, same orientation, moved? → Translation
- Same size, different orientation, turned? → Rotation
Common Mistakes
- Incomplete description of rotation: A rotation needs three things — centre of rotation, angle, and direction (clockwise or anticlockwise) — missing any one loses marks
- Incomplete description of reflection: Always state the equation of the mirror line (e.g. y = x, x = 2) — "reflected horizontally" is not enough
- Incomplete description of enlargement: State the centre of enlargement AND the scale factor — a negative scale factor means the image is on the opposite side
- Forgetting translation vector notation: Write translations as a column vector — "3 right, 2 down" should be written as the vector (3, −2)
This topic summary covers Knowledge Organiser: Transformations within Transformations for GCSE Mathematics. Revise Transformations in Geometry & Measures for GCSE Mathematics with 16 exam-style questions and 5 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 6 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Transformations
A translation is described by the vector (3, −2). What does this mean?
Shape A is mapped to shape B by a translation. Describe fully what information is needed to describe a translation.
Quick recall flashcards
Reflection
State the MIRROR LINE (equation). Shape flips over. Points and images are equidistant from mirror line.
Rotation
State CENTRE, ANGLE, and DIRECTION (CW/ACW). Shape turns around fixed point. 180° is same CW or ACW.