Also find the sloping distance $b$ from the top of the roof to the top of the walls.
The hottest part of the day is when the sun is directly overhead. The roof overhangs by a distance $a$ and it shades all the windows from the sun while the sun's rays are inclined at 8 degrees or less to the vertical. The lowest part of the windows is one metre above the ground and the angle $\phi$ in the diagram is 8 degrees. Find the length of the overhang, $a$.