# math

The formula for the surface area of a cylinder is A=2πr^2+2πrh. (A)Solve for r and simplify the result, if possible. (B) If the surface area of a cylinder is 100 square feet and the height is 40 inches, what is the radius of the cylinder in units of feet? Round your answer to the nearest tenth of a foot. (C) What is this radius in inches? Please help!!!!:(

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1. A / (2 π) = r^2 + h r ... 0 = r^2 + h r - [A / (2 π)]

using quadratic formula ... r = {-h ± √[h^2 - (2 A / π)]} / 2

B) A = 100 , h = 10/3 ... plug in to find r

C) multiply B) by 12 to get inches

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