In order to properly design a heating system for a greenhouse, the volume of air in the building needs to be determined. Find the volume of air in the greenhouse below. The length of the building is 40 feet long, the width is 20 feet long, and it is 8 feet from the ground to the gable. For the triangular prism on top, the height of the triangle is 7 feet

v = (40)(20*8 + 20*7/2)