Question

Find the measure of angle B in the following triangle

Answer 1

27.6 degrees

Explanation:

Use Cosine rule on Acute triangle

b² = a² + c² - 2ac Cos B

where b = 10, a = 14, c = 20

10² = 14² + 20² - 2(14)(20) Cos B

-496 = -560 Cos B

Cos B = (-496) / (-560)

B =
`Cos^(-1)` (-496) / (-560) = 0.483 radians = 27.6 degrees