Pentagonal pyramid

Infobox Polyhedron with net

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Polyhedron_Type=Johnson
J₁ - J₂ - J₃
Face_List=5 triangles
1 pentagon
Edge_Count=10
Vertex_Count=6
Symmetry_Group="C"_5v
Vertex_List=5(3².5)
(3⁵)
Dual=self
Property_List=

---

In geometry, a pentagonal pyramid is a pyramid with a pentagonal base upon which are erected five triangular faces that meet at a point (the vertex). Like any pyramid, it is self-dual.

The "regular" pentagonal pyramid has a base that is a regular pentagon and lateral faces that are equilateral triangles. It is one of the Johnson solids ("J"₂). It can be seen as the "lid" of an icosahedron; the rest of the icosahedron forms a gyroelongated pentagonal pyramid, "J"₁₁. The 92 Johnson solids were named and described by Norman Johnson in 1966.

More generally an order-2 vertex-uniform pentagonal pyramid can be defined with a regular pentagonal base and 5 isosceles triangle sides of any height.

External links

*
* [http://www.lifeisastoryproblem.org/explore/net_pentagonal_pyramid.pdf Printable Net of a Pentagonal Pyramid] [http://www.lifeisastoryproblem.org Life is a Story Problem.org]
* [http://www.georgehart.com/virtual-polyhedra/vp.html Virtual Reality Polyhedra] www.georgehart.com: The Encyclopedia of Polyhedra ( VRML [http://www.georgehart.com/virtual-polyhedra/vrml/pentagonal_pyramid_(J2).wrl model] )