1. The problem statement, all variables and given/known data 2. Relevant equations sine law : (A)/(sin a) = (B)/(sin b) = (C)/(sin c) cosine law : c^2 = ( (a^2) + (b^2) - (a)(b)(cos A) vector addition : R^2 = (Rx)^2 + (Ry)^2 = ((Ax + Bx +Cx)i )^2 + ((Ay + By + Cy)j )^2 3. The attempt at a solution Well, I'm completely stumped as to how to finish this, or even if I'm on the right track. Any one able to help?