3) The City of Oz has to repaint its cylinder-shaped water tower. Only the top and sides need to be painted. If the water tower has a height of 60 feet and a radius of 20 feet, how many square feet must be painted? A) 400π ft2 Eliminate B) 2400π ft2 C) 2800π ft2 D) 4400π ft2
The formula for SA of a cylinder is 2 pi r^2 + 2 pi r h The 2 pi r^2 is for the circular top and bottom. In this case only the TOP is being painted so the 2 can be dropped. SA = pi r^2 + 2 pi h SA = pi 20^2 + 2 pi 20*60 SA = 400 pi + 2400 pi SA = 2800pi ft^2 C
