## Rotating a Shape

A shape can be rotated. When a shape is rotated, each point on the shape is turned by an angle about a centre of rotation.

## How to Rotate a Shape

Rotating a shape is easy.

## Question

Rotate the shape below by 60° clockwise about the point (3, 1). # 1

Plot the centre of rotation. In our example, the Cartesian coordinates of the centre of rotation is (3, 1). It is 3 units along the x-axis and 1 unit up the y-axis. Each point on the shape is rotated by the same amount. Let us choose a point on the shape and rotate it. We will rotate point A.

# 2

Draw a line from the centre of rotation to point A. # 3

Measure the length of this line. # 4

Measure the angle of rotation (60°) from the line. Using a protractor, find 60° clockwise from the line found. Mark this angle. # 5

Draw a line from the centre of rotation. It must be the same length as the line in Step 3 and be at the angle found in Step 4. Point A has been rotated 60° about (3, 1) to find A', the corresponding point on the rotated shape. Repeat for points B and C:  