In a right-angle triangle, if you are given the triangle sides and are asked to find the corresponding angles, you use the inverse trigonometric ratios: inverse sine, inverse cosine and inverse tangent.

Depending on what information you are given, use one of the three ratios to find your missing angle.

Here are some examples showing how to use these functions.

Note: Use your calculators when working the inverse functions.

Using the inverse sine ratio

Using the inverse cosine ratio

Using inverse tangent ratio

Bearings - three examples
Find a missing angle - non right angle triangle