I am looking for an angle, using Law of Cosines. I am trying to solve for C.
R^2= a^2+b^2- (2 X a X b X cos C)
The Attempt at a Solution
These are the numbers I am using, plugged into the Law of Cosines:
80^2= 450^2+ 373^2-(2 X 450 X 373 X cos C)
I have solved this far, Cos C= -.999
I know it's right this far, because my teacher told me it was, but I don't know how to find the angle past this point. I know I have to use inverse of cosine somehow. Please, help me, test tomorrow. Thanks.:)