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An interior designer plans to paint the surfaces of 21 pillars. Each pillar is shaped like a right cylinder. The cylinders are 12 feet high and each has a diameter of 14 inches. One gallon of paint covers 350 square feet. How many gallons of paint will the designer need to complete the job? One foot is the same as 12 inches. The tops and bottoms of the pillars will not be painted.

Respuesta :

Circumference of a circle = 2(3.1416)r
2(3.1416)(7)=43.9824in
43.9824in ÷ 12 = 3.6652 ft
3.6652 ft x 12 ft = 43.9823 ft sq.
43.9823 ft sq. x 21 = 923.6282 ft sq.
923.6382 ÷ 350 = 2.6389
3 gallons

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