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Volumes of Pyramids

What fraction is it?

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Volume is the stuff inside

• So how is a rectangular prism and a rectangular pyramid different? How much less stuff would go inside?

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The formula for Volume of a Pyramid

1 ( )( )3base area height

The hard part is the height.It is the height from the point at the topto the base, perpendicular to the base

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An example

square pyramid

8cm

9 cm

1 ( )( )3base area height

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5 6

2

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Find the ratio of similarity and the ratio of volumes

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Similarity of Solids Theorem

• if the ratio of similarity of two solids is

• then the ratio of areas is

• and the ratio of volumes is

: aa b orb

22 2

2: aa b orb

33 3

3: aa b orb

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Find the volume of the Weirdo composite shape

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