document.write( "Question 425787: how did we come up with the formula for surface area of a cylinder. \n" ); document.write( "

Algebra.Com's Answer #296379 by richard1234(7193) $\"\"$ $\"About$

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The surface of a cylinder is composed of two parts: the areas of the bases and the lateral surface area. If the base is assumed to be a circle, the area of one base is just $\"pi%2Ar%5E2\"$ so the area of both these bases is $\"2pi%2Ar%5E2\"$ . The lateral surface area is essentially a rectangle with height h and base equal to the circumference of the circle. The circumference is $\"2pi%2Ar\"$ , so the lateral surface area is $\"2pi%2Ar%2Ah\"$ . Add this with $\"2pi%2Ar%5E2\"$ to obtain the surface area. \n" ); document.write( "

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