A circle cut into thin wedges and laid in a row is almost a parallelogram, which gives the area πr². A cylinder is a stack of thin discs, so its volume is base area times height. A cube splits into three identical pyramids, and a cone pours three times into the cylinder with the same base and height, so each is one third of its prism or cylinder. The volume of a sphere is 4/3 πr³. Slicing a solid leaves a flat cross-section, and spinning a flat shape sweeps out a solid. This week the crew measures the foam props and the paint with these formulas.