Question

Use the Law of Cosines to determine the indicated angle θ?

Answer 1

In the triangle the three sides are a = 133.5, b = 60.1 and c = 159.5

Use law of cosines cosC = (a² + b² - c²)/2ab

cosC = [(133.5)² + (60.1)² - (159.5)²]/[2(133.5)(60.1)]

= [17822.5 + 3612.01 - 25440.25]/(16046.7)

= - 4005.74/16046.7

= - 0.24963

C = cos^-1 (-0.24963)

C = 104.45

θ = 104°.