Question

A triangle has sides A, B, and C. Sides A and B are of lengths `4` and `5`, respectively, and the angle between A and B is `(pi)/8`. What is the length of side C?

Answer 1

`c=sqrt(a^2+b^2-2abcosC) = sqrt(4^2+5^2-2(4)(5)cos (pi/8) )~~ 2.01`

Explanation:

Use the law of cosines and then substitute in the values for a, b, and angle C and then find side c.