Question

6. Find angle A

Law of sines and cosines

Answer 1

Explanation:

Law of cosines c^2 = a^2 + b^2 - 2ab cos Φ where Φ is the angle between sides a and b

30^2 = 20^2 + 17^2 - 2(20)(17) cos Φ Solve for cos Φ = -.31029

so Φ = 108 degrees