A home site requires excavation on a level lot to a uniform depth of 12 ft. The excavation must be 40 ft x 45 ft at the bottom of the hole. For safety, the sides of the excavation must be sloped at 1.5H:1V. This means that the excavation must get wider by 3 ft (1.5 ft on each side) in both directions for every 1 ft up from the bottom of the excavation