Question

I've worked through this problem over and over...someone help!

Answer 1

@ganeshie8 ? :)

Answer 2

law of cosines
\[a^2 = b^2 + c^2 - 2bc \cos \alpha\]

you have all you need to do this

Answer 3

What is the alpha?

Answer 4

I got it now, the answer is right. Thanks! :)