Three bricks, each having a weight W and length a, are stacked like a staircase, the top two bricks hanging over the end of the previous brick.

The bottom brick of length a lies on a flat surface and the top brick hangs over a total distance d from the bottom bricks length. Therefore, the total distance on the flat surface between the lenth of the bottom brick and the distance to the top brick overhang is a + d.

l------a------l

lTTTTTTTTl

lTTTTTTTTl

lTTTTTTTTl

l-----a-------l-----d------l

Use the equations of static equilibrium to find the distance d.

d = 3/4 a please show all steps how this answer was derived; Thanks.