Cylinder Height
posted by Sydney .
A cylinder has surface area of 402 cm2. The height is three times greater than the radius.
What is the height of the cylinder?

r = radius
3r = height (h)
SA = 2(pi)(r)(h) + 2(pi)(r^2)
SA = 2(pi)(r)(3r) + 2(pi)(r^2)
SA = 6(pi)(r^2) + 2(pi)(r^2)
SA = 8(pi)r^2
402 = 8(pi)r^2
402 = 8(3.14)r^2
402 = 25.12r^2
16.00318 = r^2
rounding 16.00318 = 16
16 = r^2
r = 4
height = 3r = 3(4) = 12 
thx

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