Question

Find X.
Round to the nearest tenth.

Law of Cosines : c2 = 22 + b2 - 2ab cos C

Answer 1

70.5°

Explanation:

22² = (20)²+(18)² - 2(20)(18) cos X

484 = 400 + 324 - 720 cos X

-240 = -720 cosx

1/3 = cos X

`cos^(-1)((1)/(3))` = X

X = 70.52877937