Three coplanar forces - A, B and C - have magnitudes of 1000N, 1200N and 1700N respectively. They act on a body such that the resultant force is zero. Find the angle between A and B. Well, I know that you can create your own axis from one of the forces. However, the solution that my teacher wrote up confuses me. They assumed one of the forces from the x axis and one of the forces started on the y axis. I have no idea why they did that because I always thought you could only assume the position of one of the forces on the X axis and work from there. However, if anyone could clarify this for me, that would be helpful. Thanks in advance.