# Rotation Turning a shape around a fixed point, called the centre of rotation, by a certain angle and direction. Maths (school) · Part 07: Shape and space · Card 2 of 9 · Last updated 2026-10-19 ## Analogy Like the hands of a clock turning round the middle. ## Example **Point (2, 1) about origin** 90 degrees anticlockwise Rule: (x, y) becomes (-y, x) New point (-1, 2) ## In practice Windmills and fairground wheels turn about a centre. ## Practice ### Flashcards - **What three things describe a rotation?** Angle, direction and centre. ### Interview questions **Describe fully the transformation that takes point (2, 1) to (-1, 2).** - It is a rotation - The angle is 90 degrees anticlockwise - The centre is the origin - Rule (x, y) becomes (-y, x) ## Questions people ask ### What three things describe a rotation? You need the angle, the direction (clockwise or anticlockwise) and the centre of rotation. Missing any one of these means the description is incomplete. A rotation of 180 degrees does not need a direction as both ways end up in the same place. ### Does rotation change the size of a shape? No. A rotation keeps the shape the same size, with the same side lengths and angles. Only its position and orientation change. That makes the original and the rotated shape congruent. This is why rotations, reflections and translations are all called congruent transformations. Only enlargement changes size. ## Related concepts - [Reflection](https://studyvisually.com/learn/science/maths-school/maths-school-part-7/maths-school-part-7-concept-1) - [Translation](https://studyvisually.com/learn/science/maths-school/maths-school-part-7/maths-school-part-7-concept-3) - [Enlargement](https://studyvisually.com/learn/science/maths-school/maths-school-part-7/maths-school-part-7-concept-4) Web page: https://studyvisually.com/learn/science/maths-school/maths-school-part-7/maths-school-part-7-concept-2 Study this card in the app: https://studyvisually.com/app/learn?category=maths-school&card=maths-school-part-7-concept-2