Английская Википедия:Elongated pyramid

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Шаблон:Short description Шаблон:Infobox polyhedron

In geometry, the elongated pyramids are an infinite set of polyhedra, constructed by adjoining an Шаблон:Nowrap pyramid to an Шаблон:Nowrap prism. Along with the set of pyramids, these figures are topologically self-dual.

There are three elongated pyramids that are Johnson solids:

Higher forms can be constructed with isosceles triangles.

Forms

name faces
Файл:Elongated triangular pyramid.png elongated triangular pyramid (J7) 3+1 triangles, 3 squares
Файл:Elongated square pyramid.png elongated square pyramid (J8) 4 triangles, 4+1 squares
Файл:Elongated pentagonal pyramid.png elongated pentagonal pyramid (J9) 5 triangles, 5 squares, 1 pentagon

See also

References

  • Norman W. Johnson, "Convex Solids with Regular Faces", Canadian Journal of Mathematics, 18, 1966, pages 169–200. Contains the original enumeration of the 92 solids and the conjecture that there are no others.
  • Шаблон:Cite book The first proof that there are only 92 Johnson solids.

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