SOLUTION: The surface area of a cylinder is 200 cm ^2. The diameter is equal to the height. Find the radius. How do I solve this problem?

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Question 854201: The surface area of a cylinder is 200 cm ^2. The diameter is equal to the height. Find the radius.
How do I solve this problem?
Found 2 solutions by aditya2117, richwmiller:
Answer by aditya2117(32) About Me  (Show Source):
You can put this solution on YOUR website!
Let the radius be r and height be h cm.
h = diameter = 2r
Now,
2*22/7*r(r+h)=200
=> r(r+2r)=200*7/2*22
=> 3r^2 = 100 * 7/22
=> r^2 = 700/66
=> r = 0.4 cm (approx.)
Ans: Radius is 0.4 cm (approx.)

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
S = 2 pi r (r+h)
200 = 2 pi h/2 (h/2+h)
h = 6.5147
diameter =h
or
diameter/2=radius=6.5147/2
200 = 2 pi r (r+2r)
r = 3.2574