The three angles in a triangle add up to \(180^\circ\). If two of the angles are known then the third can be calculated by following these steps: Add the two known angles together. Subtract the total ...

Revise using the sine and cosine rules to find a side or angle in a triangle for National 5 Maths. National 5 Maths - Using the sine and cosine rules to find a side or angle in a triangle.