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Surface Area of Prism
By Swati on June 16, 1998:

For the surface area of a prism the formula given in our book is:
perimeter of base × height + 2 ×(base area)

You follow it to get the answer but what I don't get is how the FORMULA itself works to give the answer. Thanks

By Gordon (gtyl2) on June 17, 1998:

If I want to be extrememly technical, I can go into integration, but I don't think it will help you much.

Basically, the idea of the formula is this. Split the prism into 3 bits: The two ends and the side.

The two ends are given by the area of the cross-section of the prism: So it is just 2 x base area.

The last term expresses the surface area, imagine we wrap the prism with a label like the ones you get on a tin can very tightly. Now assume that the label covers all the side exactly.

Unwrap it, we get a rectangle. The area of the rectangle is just the height x perimeter. Add the two terms up, we get the total surface area.

Gordon