Sunday, 17 August 2008

Pyramid - An Ancient Shape

Geometry has lasted a long time ago.

The Egyptian Pyramids of Giza in Egypt is a famous example.

What is so special about the shape of this pyramid?

It differs from other shape in that, besides the base, all its other surfaces end up in a vertex, or pointed tip at one end.

Actually this pyramid is closely related to the prism. In fact, pyramid is part of the prism, and therefore is mathematically linked.

The volume of a prism is given as
"Area of Base x Height".

The volume of the pyramid is thus given as one-third that of the prism.

In other words, volume of pyramid = (1/3) x (Area of Base) x Height.

For more information about this volume relationship and why is it one-third, you may read Volume of Common Solids.

To better understand pyramid, test yourself with the question below.

Look at the diagram below and tell which volume is the biggest.
Note that they have the same base area and height, but has different slanting angles.

Any ideas? Read on for the answer...


The answer is that they are all equal in volume.

This is because the angle of the slanted edge does not play a part in the computation the pyramid volume. The formula tells the "story".

After understanding the concept of pyramid, do you have a better admiration for the "Great Pyramids" of Egypt?

I sure do! :)

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