Question

Using the Law of Cosine solve for the unknown. Given: side c = 68.7, side a=46, side b=46 find angle

A =?

Answer 1

Given sides of triangle a = 46, b = 46, c = 68.7

To find angle A, use law of cosines.

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

=[46^2+68.7^2-46^2]/[2(46)(68.7)]

= [2116+4719.69-2116]/6320.4

= 0.7467

A = Cos^-1(0.7467)

A = 41.6946

A = 41.7