## The Lesson

A rotation turns a shape. A rotation is a turn of a shape about a point (called the centre of rotation). A translation is a type of transformation.## A Real Example of a Rotation

It is easier to understand rotation with an example. The diagram below shows a rotation of a shape. The shape before the rotation (called the**object**) is in light blue. The shape after the rotation (called the

**image**) is in dark blue:In this example, the shape has rotated around a centre of rotation (shown as a red cross) at the origin.

## Properties of a Rotation

- All points move in a circle around the centre of rotation.
- Each point in the image is the same distance from the centre of rotation as the object.
- The image is the same size as the object.

## Rotated Shapes Are Congruent Shapes

If a shape can be transformed to another using only rotation, then the two shapes are**congruent**. Congruent shapes have the same size, line lengths, angles and areas. They are the same shape and size, just in a different position.