Math 10
posted by Caitlin .
A cylinder has a surface area of 250cm2. The height is twice as big as the radius. What is the height of the cylinder?

h = 2r
SA = 2πr^2 + 2πrh
= 2πr^2 + 2πr(2r)
= 6πr^2
6πr^2 = 250
r^2 = 125/(3π)
r = 3.6418..
h = 2r = 7.28....