Question

Solve for the measure of each angle. Trigonometry.

Answer 1

∠A=26º

∠B=137º

∠C=17º

Explanation:

We can use the Law of Cosines because we have all 3 side lengths.

cosA =
`b^2+c^2-a^2/2bc`

cosA=28^2+12^2-18^2 / 2(28)(12)

cosA=604/672

cos-1(604/672

angle A ≈ 26º

cosB =
`c^2+a^2-b^2/2ca`

cosB=-316/432

cos-1(-316/432

angle B ≈ 137º

26+137=163

180-163=17

angle C ≈ 17º