Derivation of the surface area of a cylinder

See also: Surface area of a cylinder
Try this Drag the orange dot to the left to "unroll" the cylinder.

The surface area of a cylinder can be found by breaking it down into three parts:

In the figure above, drag the orange dot to the left as far as it will go. You can see that the cylinder is made up of two circular disks and a rectangle that is like the label unrolled off a soup can.

Combining these parts we get the final formula: where:
π  is Pi, approximately 3.142
r  is the radius of the cylinder
h  height of the cylinder

By factoring 2πr from each term we can simplify this to However, the first is the one shown in most textbooks and more clearly shows how it is derived.

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