Question

In △ABC,c=9, m∠B=65°, and a=105. Find b.

Answer 1

b ≈ 101.52

Explanation:

Given two sides and the angle between, the Law of Cosines is useful.

b^2 = a^2 +c^2 -2ac·cos(B)

b^2 = 105^2 +9^2 -2·105·9·cos(65°) ≈ 10307.251

b ≈ √10307.251

b ≈ 101.52