What is a Pyramid? - Square Pyramids
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What is a pyramid?


A pyramid is a three-dimensional solid form made out of triangles, and sometimes a square. There are two common kinds of pyramids: triangular pyramids that you make by fitting four triangles together, and square pyramids that you make by fitting four triangles together on a square base, like the one in the picture here. The pyramids of Egypt are square pyramids. You can also have pyramids with hexagonal or octagonal bases, or however many sides you like. If the base has an infinite number of sides, then it's a circle, and the resulting solid shape is not a pyramid but a cone.

To calculate the surface area of a pyramid, you need to calculate the area of each of the triangles (or the triangles and the square) involved and then add them together.

To calculate the volume of a pyramid, first calculate the volume of the rectangular solid around the pyramid. That's the area of the base multiplied by the height of the pyramid. Then divide that by three, because the pyramid doesn't fill up the whole volume of the rectangular solid around it.

More about cones
More about Geometry

Bibliography and further reading about geometry:

More about Geometry
More Easy Math
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Professor Carr

Karen Eva Carr, PhD.
Assoc. Professor Emerita, History
Portland State University

Professor Carr holds a B.A. with high honors from Cornell University in classics and archaeology, and her M.A. and PhD. from the University of Michigan in Classical Art and Archaeology. She has excavated in Scotland, Cyprus, Greece, Israel, and Tunisia, and she has been teaching history to university students for a very long time.

Professor Carr's PSU page

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