Mathematica 2014

25

Cavalieri’s Principle tells us the volumes of these pyramid equal one another.

2 Initial steps To begin with, we need to define the volume of cube and cuboid. 2.1 Cube

ܽ 3 , where

ܽ is the length of one side.

We postulate the volume of a cube is

2.2 Cuboid

ሺܽ ൈ ܾ ൈ ܿሻ . Then

Suppose three values a, b, c which are the sides of a cuboid

ܽ ൅ ܾ ൅ ܿ . According to our axiom, the

we form a cube with the side length of

volume of this cube would be ሺܽ ൅ ܾ ൅ ܿሻ 3 : ሺܽ ൅ ܾ ൅ ܿሻ 3 ൌ ܽ 3 ൅ ܾ 3 ൅ ܿ 3 ൅ 3ܾܽܿሺܽ ൅ ܾ ൅ ܿሻ ֜ ሺܽ ൅ ܾ ൅ ܿሻ 3 ൅ ܽ 3 ൅ ܾ 3 ൅ ܿ 3 ൌ ሺܽ ൅ ܾሻ 3 ൅ ሺܽ ൅ ܿሻ 3 ൅ ሺܾ ൅ ܿሻ 3 ൅ 6ܾܽܿ ൌ ሺܽ ൅ ܾሻ3 ൅ ሺܽ ൅ ܿሻ3 ൅ ሺܾ ൅ ܿሻ3 ൅ 6ܾܽܿ Then we divide the big cube into 3 cubes which have a 3 , b 3 , c 3 cubes intersecting. Therefore, the remaining pieces are 6 cuboids; the volume of each would be ܽ ൈ ܾ ൈ ܿ . Accordingly, the volume of a cuboid would be : ܪ ݄݁݅݃ ݐ ൈ ܮ ݁݊݃ ݐ ݄ ൈ ܹ݅݀ ݐ ݄ . 3 Implementation In this section we try to work out the volume of some common shapes using the introduced principle. 3.1 Pyramid Let’s define “perfect pyramid”. The base of a perfect pyramid is a rectangle and the height is one of its sides.

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