SOLUTION: How do you find the surface area of a cylinder

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Question 294934: How do you find the surface area of a cylinder
Found 2 solutions by richwmiller, PRMath:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
With the formula for the surface area of a cylinder and the right info.

Answer by PRMath(133) About Me  (Show Source):
You can put this solution on YOUR website!
Think of a cylinder like a can of pop, k?
At the top of the can, there is a circle. At the bottom of the can, there is a circle. Now if you cut off the top and you cut off the bottom and sort of spread out the can (uncurled it), you'd have a rectangle.

Now picture this:
The height of the rectangle is the height of the can. Can you picture that?
The top of the rectangle is REALLY the the circumference of the circle. How so? Think about it -- it was a circle until you uncurled it. So the measure of the circumference of the can will not change simply because you uncurled it, right?

Sooooo to get the total surface area of the cylinder, you use this equation:

FIRST find the "lateral area" (the rectangle) which is: 2%28pi%29r+h
r is the radius
h is the height

NEXT find the areas of two bases (the top and bottom of the can). The area formula for ONE circle is: Area = %28pi%29r%5E2.
r is the radius.

HOWEVER -- there are TWO circles (the TOP and the BOTTOM of the can) soooo, we have to find the TWO bases so our formula for the TWO bases is: 2%28pi%29r%5E2


IF we add the lateral area plus the base areas, we'll know the total surface area.


Our final equation is:

Total Area of a Cylinder = 2%28pi%29rh + 2%28pi%29r%5E2

Just put in the correct numbers for the radius and height and do the math and voila - you'll have the total surface area.

If you need more help, just get a specific question (such as the measurements of a sample problem) and post it here. I'm sure someone can give you more info if you need it.

I hope this helps. :-)