👉 Learn how to find a missing angle of a right triangle. A right triangle is a triangle that has 90 degrees as one of its ...

There are two versions of the cosine rule: Find an unknown side using 𝑎² = 𝑏² + 𝑐² – 2𝑏𝑐 cos𝐴 Find an unknown angle using cos𝐴 = \(\frac{𝑏² + 𝑐² – 𝑎²}{2𝑏𝑐}\) Scientific calculators need to ...

Being able to identify which formula to use, sine or cosine, and when, is necessary to answer questions on this topic successfully. Check you are confident in how to use the sine and cosine rules.