Question

A triangle has sides A, B, and C. Sides A and B are of lengths `7` and `2`, respectively, and the angle between A and B is `(3pi)/8`. What is the length of side C?

Answer 1

Length of side `color(purple)(c = 5`

Explanation:

Given : `a = 7, b = 2, hatC = (3pi)/8`

`color(white)(aaaaaaaaaaa)` Applying Law of Cosines

`c^2 = a^2 + b^2 - 2ab cos C`

`c^2 = 7^2 + 2^2 - (2 *7*2*cos((3pi)/8) = 25`

`c = 5`