# A triangle has sides A, B, and C. Sides A and B are of lengths #7# and #6#, respectively, and the angle between A and B is #(5pi)/8 #. What is the length of side C?

##### 1 Answer

Jan 1, 2016

This problem may be solved easily by using the law of cosines.

#### Explanation:

Given a triangle, with sides

For example, to calculate the length of

In our case: