- Square pyramid
Infobox Polyhedron with net
J92 - J1 - J2
Johnson solid (J1)
If the sides are all
equilateral triangles, the pyramid is one of the Johnson solids (J1). The 92 Johnson solids were named and described by Norman Johnsonin 1966.
The Johnson square pyramid can be characterized by a single edge-length parameter "a". The area "A" (including all five faces) and the volume "V" of such a pyramid are:::
Other square pyramids
Other square pyramids, such as the have
isoscelestriangle sides. For example the Great Pyramid of Giza, has isosceles triangles of base 756 feet and slant height719 feet. That pyramid has the interesting property that the slant height (along the bisector of a face) is very nearly equal to the golden ratiotimes the height, in which case the area of each triangular face is equal to the square of the pyramid's height.
For square pyramids in general, with base length "l" and height "h", the volume is: :
Like all pyramids, the square pyramid is self-dual, containing the same number of vertices and faces.
A square pyramid can be represented by the
Bipyramid- A bipyramid is two pyramids connected base to base.
* [http://polyhedra.org/poly/show/45/square_pyramid Square Pyramid] -- Interactive Polyhedron Model
* [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/square_pyramid_(J1).wrl model] )
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