Look at this diagram which shows four right angles placed next to each other at a point.

Here is one right angle, which is 90°.

Here are two right angles put together, giving an angle of 180°.

2 × 90° = 180°

Here are three right angles put together, giving an angle of 270°.

3 × 90° = 270°

Here are four right angles put together, giving an angle of 360°.

4 × 90° = 360°

Let's have a go at some questions now.