Question

In triangle ABC, a = 9, c = 5, and B = 120°. Find b2.

Answer 1

This can be solved using the cosine law wherein two sides are given with the angle between the two sides to find the third side.

$b^{2}$ =  $a^{2}$ + $c^{2}$ -2ac cosФ 

= $9^{2}$ + $5^{2}$ -2(9)(5) cos 120

$b^{2}$= 151

b =12.29 is the length of the third side

Answer 2

Answer:

b = 12.3

Step-by-step explanation:

and A is 39