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A pyramidal frustum is a frustum made by chopping the top off a pyramid. It is a special case of a prismatoid.
For a right pyramidal frustum, let 
be the slant height, 
the height, 
the bottom base perimeter,
the top base perimeter,
the bottom area,
and 
the top area. Then the surface
area (of the sides) and volume of a pyramidal frustum
are given by
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(1)
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(2)
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The geometric centroid of a right pyramidal frustum occurs at a height
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(3)
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above the bottom base (Harris and Stocker 1998).
The bases of a right 
-gonal
frustum are regular polygons of side lengths 
and 
with circumradii
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(4)
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where 
is the side length, so the diagonal connecting corresponding vertices on top and
bottom has length
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(5)
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and the edge length is
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(6)
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(7)
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The triangular (
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and square (
)
right pyramidal frustums therefore have side surface areas
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(8)
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(9)
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The area of a regular 
-gon is
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(10)
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so the volumes of these frustums are
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(11)
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(12)
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