What are the formulas for find the surface area of a cone and a cylinder?

The surface area of a cone is A = πrl where l is the slant height of the cone (if you don’t know it, but know the height and radius, you can use the Pythagorean Theorem).

You can find the proof here:
http://www.allendesigns.com/AreaofCone/AreaofCone.htm

For a cylinder, the surface area is:

A = 2πr² + 2πrh

For the cylinder, we compute the area of the top and bottom (which are just two congruent circles), plus the lateral area (which is just a rectangle with it’s height being the height of the cylinder and the width being the perimeter of either base).

I hope this helps!

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One Response to “What are the formulas for find the surface area of a cone and a cylinder?”

θ βяιαη θ on January 31st, 2010 at 9:39 am

The surface area of a cone is A = πrl where l is the slant height of the cone (if you don’t know it, but know the height and radius, you can use the Pythagorean Theorem).

You can find the proof here:
http://www.allendesigns.com/AreaofCone/AreaofCone.htm

For a cylinder, the surface area is:

A = 2πr² + 2πrh

For the cylinder, we compute the area of the top and bottom (which are just two congruent circles), plus the lateral area (which is just a rectangle with it’s height being the height of the cylinder and the width being the perimeter of either base).

I hope this helps!
References :

Area List