Question

In triangle ABC, angle A = 74°, a = 126, and b = 84. Find angle B.

A. 39.9°
B. 79.4°
C. 80.8°
D. impossible to tell

Answer 1

Explanation:

We are given three information about a triangle

angle A = 74°, a = 126, and b = 84

we can use the sine law to find the angle B

It is

`sin B =(b)/(a)sin A`

so plugging all the known values we get

`sin B = (84)/(126)sin(74)`

`sin B =0.64084`

`B= sin^(-1)(0.64084)`

B =39.85

so it rounds to

angle B =39.9°

Option A