GCSE Cosine rule

Finding the length of a side of a non right angled triangle

In this tutorial, I show you how to find a length of a side of a non-right-angled triangle by using the Cosine Rule.

You can do this if you are given the opposite angle and the two other sides.

Finding an angle of a non right angled triangle

In this tutorial, I show you how to find an angle of a non-right-angled triangle using the Cosine Rule.

You can do this if you are given the lengths of all 3 sides.

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