Question: Minimize the cost of constructing a cylindrical storage tank. The tank must hold 57,600 gallons and be constructed from two rectangular sheets of steel. The sheet that is rolled to form the cylinder walls costs $2.75 per square foot. The sheet that forms the circular ends of the cylinder costs $5.50 per square foot. The cutting of the circles out of the rectangle costs $.50 per linear foot. The rolling of the rectangular sheet into a cylinder costs $.60 per linear foot. The welding of the pieces to make the cylinder costs $.70 per linear foot. The tank must have two coats of rust preventer on the inside of the tank and one on the outside, and it must have two coats of metallic paint on the outside of the tank. The rust preventer costs $.25 per square foot, and the metallic paint costs $.40 per square foot.