I've attached a picture of my problem (with diagram): 4.70 .
"For the frame and loading show, determine the reactions at A and C."
From the diagram, you can see that the metal object is made up of 2 parts:
1) A to B
2) B to D
The Attempt at a Solution
how do you arrive at the correct direction of the forces (ie: angle of the force; direction of its "application"). I have 2 interpretations and they will give different angles with which the force is applied (same magnitudes though). Which one is the correct interpretation? Because this is a statics problem (bodies at equilibrium), the sum of the forces = 0 (illustrated by the triangles).
How do you logically determine which interpretation (of force directions) is correct when you do these problems?