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The dual of a cube is an octahedron.Vertices of one correspond to faces of the other, and edges correspond to each other. In geometry, every polyhedron is associated with a second dual structure, where the vertices of one correspond to the faces of the other, and the edges between pairs of vertices of one correspond to the edges between pairs of faces of the other. [1]
The illustration here shows the vertex figure (red) of the cuboctahedron being used to derive the corresponding face (blue) of the rhombic dodecahedron.. For a uniform polyhedron, each face of the dual polyhedron may be derived from the original polyhedron's corresponding vertex figure by using the Dorman Luke construction. [2]
A polyhedron with only equilateral triangles as faces is called a deltahedron. There are eight convex deltahedra, one of which is a triangular bipyramid with regular polygonal faces. [ 1 ] A convex polyhedron in which all of its faces are regular polygons is the Johnson solid , and every convex deltahedron is a Johnson solid.
The rhombic dodecahedron is a Catalan solid, meaning the dual polyhedron of an Archimedean solid, the cuboctahedron; they share the same symmetry, the octahedral symmetry. [2] It is face-transitive , meaning the symmetry group of the solid acts transitively on its set of faces.
Since the quadrilaterals are chiral and non-regular, the dyakis dodecahedron is a non-uniform polyhedron, a type of polyhedron that is not vertex-transitive and does not have regular polygon faces. It is an isohedron, [4] meaning that it is face transitive. The dual polyhedron of a dyakis dodecahedron is the cantic snub octahedron.
A Goldberg polyhedron is a dual polyhedron of a geodesic polyhedron. A consequence of Euler's polyhedron formula is that a Goldberg polyhedron always has exactly 12 pentagonal faces. Icosahedral symmetry ensures that the pentagons are always regular and that there are always 12 of them.
Many traditional polyhedral forms are n-dimensional polyhedra. Other examples include: A half-space is a polyhedron defined by a single linear inequality, a 1 T x ≤ b 1.; A hyperplane is a polyhedron defined by two inequalities, a 1 T x ≤ b 1 and a 1 T x ≥ b 1 (which is equivalent to -a 1 T x ≤ -b 1).
There are five uniform ditrigonal polyhedra, all with icosahedral symmetry. [1] The three uniform star polyhedron with Wythoff symbol of the form 3 | p q or 3 / 2 | p q are ditrigonal, at least if p and q are not 2. Each polyhedron includes two types of faces, being of triangles, pentagons, or pentagrams.