Two men decide to use their cars to pull a
 truck stuck in mud. They attach ropes and
 one pulls with a force of 515 N at an angle
 of 31◦ with respect to the direction in which
 the truck is headed, while the other car pulls
 with a force of 926 N at an angle of 25◦ with
 respect to the same direction. What is the net forward force exerted on
 the truck in the direction it is headed?