If a full turn equals 360º, then the sum of the angles around a point must also be 360º. When you calculate angles around a point, you can use this fact to find the missing angles.

National 5 Using the sine and cosine rules to find a side or angle in a triangle The cosine rule The sine rule can be used to find an angle from 3 sides and an angle, or a side from 3 angles and a ...