Angles on a line and round a point

Angles that sit together on a straight line add up to 180°. Angles all the way around a point add up to 360°.

Key facts

  • Angles on a straight line add up to 180°.
  • Angles around a point add up to 360°.
  • Vertically opposite angles (an X shape) are equal.

Worked examples

Example 1

Find the angle x.

  1. The two angles make a straight line. x + 125 = 180
  2. Take 125 away from 180. x = 180 − 125 = 55°

Answer: x = 55°

Questions about angles on a line and round a point