Question

Use the Law of Sines to find the missing angle of the triangle. Find m<b to the nearest tenth.

A) 110.0 degrees
B) 153.9 degrees
C) 26.1 degrees
D) 70.0 degrees

Answer 1

1. By the Law of Sines, you have:

SinA/a=SinB/b=SinC/c

2. You don't need the fraction SinC/c, so you can eliminate it. Then:

SinA/a=SinB/b

A=40°
a=19
B=m∠b
b=13

3. When you substitute this values into SinA/a=SinB/b, you obtain:

SinA/a=SinB/b
Sin(40°)/19=SinB/13
SinB=13xSin(40°)/19
m∠b=SinB^-1(13xSin(40°)/19)
m∠b=26.1°

Therefore, the answer is: 26.1 degrees.