Frustum

Set of pyramidal right n-gonal frustums
Examples: right pentagonal and square frustums
(n = 5 and n = 4)
Facesn isosceles trapezoids, 2 regular n-gons
Edges3n
Vertices2n
Symmetry groupCnv, [1,n], (*nn)
Dual polyhedronasymmetric bipyramid
Propertiesconvex
Net
Example: net of right trigonal frustum (n = 3)

In geometry, a frustum (Latin for 'morsel');[a] (pl.: frusta or frustums) is the portion of a solid (normally a pyramid or a cone) that lies between two parallel planes cutting the solid. In the case of a pyramid, the base faces are polygonal and the side faces are trapezoidal. A right frustum is a right pyramid or a right cone truncated perpendicularly to its axis;[3] otherwise, it is an oblique frustum. In a truncated cone or truncated pyramid, the truncation plane is not necessarily parallel to the cone's base, as in a frustum. If all its edges are forced to become of the same length, then a frustum becomes a prism (possibly oblique or/and with irregular bases).

  1. ^ Clark, John Spencer (1895). Teachers' Manual: Books I–VIII. For Prang's complete course in form-study and drawing, Books 7–8. Prang Educational Company. p. 49.
  2. ^ Fontaine, Michael (2010). Funny Words in Plautine Comedy. Oxford University Press. pp. 117, 154. ISBN 9780195341447.
  3. ^ Kern, William F.; Bland, James R. (1938). Solid Mensuration with Proofs. p. 67.


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