A circular tower is made by placing one cylinder on top of another. Both cylinders have a height of 18 inches. The top cylinder has a radius of 7 inches and the bottom cylinder has a radius that is double that of the smaller cylinder. 18 in. 18 in. Another tower is constructed by placing the original tower on top of another cylinder with a height of 18 inches and a radius of 3 times that of the smallest cylinder. What is the total surface area of the new tower? Round your answer to the nearest hundredth.

A wedding tent is built in the shape of a right rectangular prism topped with a rectangular pyramid. The dimensions of the prism are 38 ft by 38 ft by 7 ft, and the height of the pyramid is 2 ft. Find the total volume of the tent. Round your answer to the nearest tenth if necessary.

How high must a 400 ­gallon rectangular tank be if the base is a square 3 ft 9 in. on a side? (1 cu. ft = 7.48 gallons.) Round to the nearest foot. ?

How many square inches of sheet copper are needed to cover the inside wall of a cylindrical tank 6 ft high with a 9­in. radius? (Hint: change the altitude to inches.). Round to the nearest square inch.?