A light stool in the shape of an equilateral triangle has three identical vertical legs A,B,C at the corners and sits above a horizontal ground. Choose a coordinate system and length scale so that looking from above A=(0,-1), B=(0,1) C=(sqrt3,0). Assume up and right are positive. A mass m is placed on the stool at M=(x,y). Find the force through each leg supporting the mass in terms of x,y,g and m.