Date: Thu, 24 Apr 1997 12:34:29 -0400
Subject: Formulae for surface area
Hi, kind folks.
I'm trying to help my son with his Math homework (Grade 10) and he has to find the surface area of a cone and rectangluar pyramid. We have the formulas for the volume of these solids, but can't seem to locate the formulas for surface area.
Can anyone help me out or point me to a source for such formulas?
One way to find surface area of a three dimensional figure is, if possible,
to cut it open and lay it out in the plane. Measure the
areas of the pieces in the plane and add those up:
For the rectangular pyramid: this can be slit open and seen as a rectangle plus four triangles. Depending on the information given, it may be easy to get the areas of the triangle, or it may require some trigonometry.
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