Polyhedron (nonfiction): Difference between revisions

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[[File:Dodecahedron.svg|thumb|Dodecahedron, which has twelve faces, each face the same pentagon.]]In elementary [[Geometry (nonfiction)|geometry]], a '''polyhedron''' (plural '''polyhedra''' or '''polyhedrons''') is a solid in three dimensions with flat polygonal faces, straight edges and sharp corners or vertices.
[[Polyhedra.jpg|thumb|Six different types of polyhedra.]]In elementary [[Geometry (nonfiction)|geometry]], a '''polyhedron''' (plural '''polyhedra''' or '''polyhedrons''') is a solid in three dimensions with flat polygonal faces, straight edges and sharp corners or vertices.


The word polyhedron comes from the Classical Greek πολύεδρον, as ''poly''- (stem of πολύς, "many") + -''hedron'' (form of ἕδρα, "base" or "seat").
The word polyhedron comes from the Classical Greek πολύεδρον, as ''poly''- (stem of πολύς, "many") + -''hedron'' (form of ἕδρα, "base" or "seat").

Revision as of 12:36, 20 November 2016

thumb|Six different types of polyhedra.In elementary geometry, a polyhedron (plural polyhedra or polyhedrons) is a solid in three dimensions with flat polygonal faces, straight edges and sharp corners or vertices.

The word polyhedron comes from the Classical Greek πολύεδρον, as poly- (stem of πολύς, "many") + -hedron (form of ἕδρα, "base" or "seat").

Cubes and pyramids are examples of polyhedra.

A polyhedron is said to be convex if its surface (comprising its faces, edges and vertices) does not intersect itself and the line segment joining any two points of the polyhedron is contained in the interior or surface.

A polyhedron is a 3-dimensional example of the more general polytope in any number of dimensions.

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