Question

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

Answer 1

b = 12.3

Explanation:

and A is 39

Answer 2

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