Hey PhysicsForums. Long time reader looking for some assistance 1. The problem statement, all variables and given/known data [PLAIN]http://img205.imageshack.us/img205/3923/physicsg.jpg [Broken] 2. The attempt at a solution I'm pretty sure the idea is to find the unit position vector to point A, and the force vector F. I found the unit position vector to be u = (-4/6)i +(4/6)j + (2/6)k, and the force to be F = (560cos60sin30)i + (560cos60cos30)j + (560sin60)k Dotting them together gives me 230 lb, but Mastering Engineering doesn't agree with me. Can anyone point out where I went awry? Thanks for reading!