To solve this graphically, draw a vertical vector to scale representing the 220 lb. weight. I used 1 inch = 100 lb. Then using a protractor draw the line of action for BC from the head of the weight vector and draw the line of action for AB from the tail of the weight vector. Where the two lines of action intersect shows where the head of BC and the tail of AB are. Then use a ruler and the scale to determine the magnitude of each.
Mathematically use vector components in X and Y directions and the equilibrium equations. This results in two equations with two unknowns. Different methods of linear algebra can be used to solve this system of equations. I used the method of elimination.