In a two-dimensional tug-of war, Alex, Betty, and Charles pull horizontally on an automobile
tire. The angle between Alex and Betty is 137degrees. The tire remains
stationary in spite of the three pulls. Alex pulls with a force of magnitude 220 N, and Charles
pulls with a force of magnitude 170 N. Note that the direction of the force applied by Charles
is not given. What is the magnitude of force with which Betty pulls?
F1 + F2 + F3 = 0 ?
The Attempt at a Solution
I do not know how to even approach this problem. Charles could be pulling with Betty, or with Alex, or in some other random direction. What formula could I use that would compensate for Charles?