Question

In triangle ABC a=34 b=18 and c=17 Find m?A

Answer 1

Use cousine law.
34^2 = 18^2 + 17^2 -2(18)(17) cosA
A = 153°
Therefore, angle A is 153°

Answer 2

152.53°

Explanation:

The Law of Cosines is useful for finding an angle when sides are given.

a^2 = b^2 +c^2 -2bc·cos(A)

A = arccos((b^2 +c^2 -a^2)/(2bc))

A = arccos((18^2 +17^2 -34^2)/(2(18)(17))) = arccos(-543/612)

A ≈ 152.53°