A rigid body subjected to three forces acting at three different points is called a three-force member. The line of action of these forces must be concurrent, except for parallel forces where the lines of action are parallel. Consider a dumpster connected to a pin support at point A and a pin attached to a hydraulic cylinder at point B. The hydraulic cylinder is a two-force member in equilibrium. The force due to the weight acts through the center of gravity, and the reaction forces due to the support act at point A. The first step involves drawing a free-body diagram of the system that includes all the forces acting on the dumpster. The force and moment equilibrium equations can be used to determine the unknown forces FA and FCB. Then, the moment equilibrium condition at point A calculates the force FCB. The force equilibrium condition along the vertical direction gives the vertical reaction force. Similarly, applying the force equilibrium condition along the horizontal direction yields the horizontal reaction force.