Question

In triangle abc, a = 9, c = 5, and b = 120. Find b2. 61 83.5 128.5 151

Answer 1

Answer:

151

Step-by-step explanation:

Given  

In triangle abc, a = 9, c = 5, and b = 120. Find b^2

We need to draw and observe angle 120 degree. Let A = 9 and C = 5

Using law of cosines we can find side b.

So b^2 = a^2 + c^2 – 2 x a x c x cos b

  b^2 = a^2 + c^2 – 2 x a x c x cos 120

  b^2 = 81 + 25 – 2 x 9 x 5 x (-1/2)

  b^2 = 81 + 25 + 45

  b^2 = 151