SOLUTION: the surface area of a cylinder is 1000 pi square centimeters. the radius of the cylinder is four times the height. what is the height of the cylinder. only reply if u see this with

Algebra ->  Surface-area -> SOLUTION: the surface area of a cylinder is 1000 pi square centimeters. the radius of the cylinder is four times the height. what is the height of the cylinder. only reply if u see this with      Log On


   

Question 737621: the surface area of a cylinder is 1000 pi square centimeters. the radius of the cylinder is four times the height. what is the height of the cylinder. only reply if u see this within 2 hours. its very time sensitive
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
the surface area of a cylinder is 1000 pi square centimeters.
the radius of the cylinder is four times the height.
what is the height of the cylinder.
:
LET x = the height
"radius is 4 time the height" therefore
4x = the radius
:
S.A. = 2%2Api%2Ar%5E2 + 2%2Api%2Ar%2Ah
so we have
2%2Api%2A%284x%29%5E2 + 2%2Api%2A%284x%29%2Ax = 1000pi
divide equation by 2pi
%284x%29%5E2+%2B+4x%2Ax = 500
16x%5E2+%2B+4x%5E2 = 500
20x%5E2 = 500
divide both sides by 20
x%5E2 = 25
x = sqrt%2825%29
x = 5 is the height
:
You can check the math on this,