Set of uniform n-gonal prisms | |
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![]() Example: uniform hexagonal prism (n = 6) | |
Type | uniform in the sense of semiregular polyhedron |
Faces | 2 n-sided regular polygons n squares |
Edges | 3n |
Vertices | 2n |
Vertex configuration | 4.4.n |
Schläfli symbol | {n}×{ } [1] t{2,n} |
Conway notation | Pn |
Coxeter diagram | ![]() ![]() ![]() ![]() ![]() |
Symmetry group | Dnh, [n,2], (*n22), order 4n |
Rotation group | Dn, [n,2]+, (n22), order 2n |
Dual polyhedron | convex dual-uniform n-gonal bipyramid |
Properties | convex, regular polygon faces, isogonal, translated bases, sides ⊥ bases |
Net | |
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Example: net of uniform enneagonal prism (n = 9) |
In geometry, a prism is a polyhedron comprising an n-sided polygon base, a second base which is a translated copy (rigidly moved without rotation) of the first, and n other faces, necessarily all parallelograms, joining corresponding sides of the two bases. All cross-sections parallel to the bases are translations of the bases. Prisms are named after their bases, e.g. a prism with a pentagonal base is called a pentagonal prism. Prisms are a subclass of prismatoids. [2]
Like many basic geometric terms, the word prism (from Greek πρίσμα (prisma) 'something sawed') was first used in Euclid's Elements. Euclid defined the term in Book XI as “a solid figure contained by two opposite, equal and parallel planes, while the rest are parallelograms”. However, this definition has been criticized for not being specific enough in regard to the nature of the bases (a cause of some confusion amongst generations of later geometry writers). [3] [4]
An oblique prism is a prism in which the joining edges and faces are not perpendicular to the base faces.
Example: a parallelepiped is an oblique prism whose base is a parallelogram, or equivalently a polyhedron with six parallelogram faces.
A right prism is a prism in which the joining edges and faces are perpendicular to the base faces. [5] This applies if and only if all the joining faces are rectangular .
The dual of a rightn-prism is a rightn-bipyramid.
A right prism (with rectangular sides) with regular n-gon bases has Schläfli symbol { }×{n}. It approaches a cylinder as n approaches infinity. [6]
Note: some texts may apply the term rectangular prism or square prism to both a right rectangular-based prism and a right square-based prism.
A regular prism is a prism with regular bases.
A uniform prism or semiregular prism is a right prism with regular bases and all edges of the same length.
Thus all the side faces of a uniform prism are squares.
Thus all the faces of a uniform prism are regular polygons. Also, such prisms are isogonal; thus they are uniform polyhedra. They form one of the two infinite series of semiregular polyhedra, the other series being formed by the antiprisms.
A uniform n-gonal prism has Schläfli symbol t{2,n}.
Family of uniform n-gonal prisms | |||||||||||||
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Prism name | Digonal prism | (Trigonal) Triangular prism | (Tetragonal) Square prism | Pentagonal prism | Hexagonal prism | Heptagonal prism | Octagonal prism | Enneagonal prism | Decagonal prism | Hendecagonal prism | Dodecagonal prism | ... | Apeirogonal prism |
Polyhedron image | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ... | |
Spherical tiling image | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | Plane tiling image | ![]() | |||
Vertex config. | 2.4.4 | 3.4.4 | 4.4.4 | 5.4.4 | 6.4.4 | 7.4.4 | 8.4.4 | 9.4.4 | 10.4.4 | 11.4.4 | 12.4.4 | ... | ∞.4.4 |
Coxeter diagram | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ![]() ![]() ![]() ![]() ![]() | ... | ![]() ![]() ![]() ![]() ![]() |
The volume of a prism is the product of the area of the base by the height, i.e. the distance between the two base faces (in the case of a non-right prism, note that this means the perpendicular distance).
The volume is therefore:
where B is the base area and h is the height.
The volume of a prism whose base is an n-sided regular polygon with side length s is therefore:
The surface area of a right prism is:
where B is the area of the base, h the height, and P the base perimeter.
The surface area of a right prism whose base is a regular n-sided polygon with side length s, and with height h, is therefore:
![]() P3 | ![]() P4 | ![]() P5 | ![]() P6 | ![]() P7 | ![]() P8 |
The symmetry group of a right n-sided prism with regular base is Dnh of order 4n, except in the case of a cube, which has the larger symmetry group Oh of order 48, which has three versions of D4h as subgroups. The rotation group is Dn of order 2n, except in the case of a cube, which has the larger symmetry group O of order 24, which has three versions of D4 as subgroups.
The symmetry group Dnh contains inversion iff n is even.
The hosohedra and dihedra also possess dihedral symmetry, and an n-gonal prism can be constructed via the geometrical truncation of an n-gonal hosohedron, as well as through the cantellation or expansion of an n-gonal dihedron.
A truncated prism is formed when prism is sliced by a plane that is not parallel to its bases. A truncated prism's bases are not congruent, and its sides are not parallelograms. [7]
A twisted prism is a nonconvex polyhedron constructed from a uniform n-prism with each side face bisected on the square diagonal, by twisting the top, usually by π/n radians (180/n degrees) in the same direction, causing sides to be concave. [8] [9]
A twisted prism cannot be dissected into tetrahedra without adding new vertices. The smallest case: the triangular form, is called a Schönhardt polyhedron.
An n-gonal twisted prism is topologically identical to the n-gonal uniform antiprism, but has half the symmetry group: Dn, [n,2]+, order 2n. It can be seen as a nonconvex antiprism, with tetrahedra removed between pairs of triangles.
3-gonal | 4-gonal | 12-gonal | |
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![]() Schönhardt polyhedron | ![]() Twisted square prism | ![]() Square antiprism | ![]() Twisted dodecagonal antiprism |
A frustum is a similar construction to a prism, with trapezoid lateral faces and differently sized top and bottom polygons.
A star prism is a nonconvex polyhedron constructed by two identical star polygon faces on the top and bottom, being parallel and offset by a distance and connected by rectangular faces. A uniform star prism will have Schläfli symbol {p/q} × { }, with p rectangles and 2 {p/q} faces. It is topologically identical to a p-gonal prism.
{ }×{ }180×{ } | ta{3}×{ } | {5/2}×{ } | {7/2}×{ } | {7/3}×{ } | {8/3}×{ } | |
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D2h, order 8 | D3h, order 12 | D5h, order 20 | D7h, order 28 | D8h, order 32 | ||
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A crossed prism is a nonconvex polyhedron constructed from a prism, where the vertices of one base are inverted around the center of this base (or rotated by 180°). This transforms the side rectangular faces into crossed rectangles. For a regular polygon base, the appearance is an n-gonal hour glass. All oblique edges pass through a single body center. Note: no vertex is at this body centre. A crossed prism is topologically identical to an n-gonal prism.
{ }×{ }180×{ }180 | ta{3}×{ }180 | {3}×{ }180 | {4}×{ }180 | {5}×{ }180 | {5/2}×{ }180 | {6}×{ }180 | |
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D2h, order 8 | D3d, order 12 | D4h, order 16 | D5d, order 20 | D6d, order 24 | |||
![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
A toroidal prism is a nonconvex polyhedron like a crossed prism, but without bottom and top base faces, and with simple rectangular side faces closing the polyhedron. This can only be done for even-sided base polygons. These are topological tori, with Euler characteristic of zero. The topological polyhedral net can be cut from two rows of a square tiling (with vertex configuration 4.4.4.4): a band of n squares, each attached to a crossed rectangle. An n-gonal toroidal prism has 2n vertices, 2n faces: n squares and n crossed rectangles, and 4n edges. It is topologically self-dual.
D4h, order 16 | D6h, order 24 |
V = 8, E = 16, F = 8 | V = 12, E = 24, F = 12 |
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A prismatic polytope is a higher-dimensional generalization of a prism. An n-dimensional prismatic polytope is constructed from two (n − 1)-dimensional polytopes, translated into the next dimension.
The prismatic n-polytope elements are doubled from the (n − 1)-polytope elements and then creating new elements from the next lower element.
Take an n-polytope with Fi i-face elements (i = 0, ..., n). Its (n + 1)-polytope prism will have 2Fi + Fi−1i-face elements. (With F−1 = 0, Fn = 1.)
By dimension:
A regular n-polytope represented by Schläfli symbol {p,q,...,t} can form a uniform prismatic (n + 1)-polytope represented by a Cartesian product of two Schläfli symbols: {p,q,...,t}×{ }.
By dimension:
Higher order prismatic polytopes also exist as cartesian products of any two or more polytopes. The dimension of a product polytope is the sum of the dimensions of its elements. The first examples of these exist in 4-dimensional space; they are called duoprisms as the product of two polygons in 4-dimensions.
Regular duoprisms are represented as {p}×{q}, with pq vertices, 2pq edges, pq square faces, pq-gon faces, qp-gon faces, and bounded by pq-gonal prisms and qp-gonal prisms.
For example, {4}×{4}, a 4-4 duoprism is a lower symmetry form of a tesseract, as is {4,3}×{ }, a cubic prism. {4}×{4}×{ } (4-4 duoprism prism), {4,3}×{4} (cube-4 duoprism) and {4,3,3}×{ } (tesseractic prism) are lower symmetry forms of a 5-cube.
In geometry, an n-gonal antiprism or n-antiprism is a polyhedron composed of two parallel direct copies of an n-sided polygon, connected by an alternating band of 2n triangles. They are represented by the Conway notation An.
In geometry, a 4-polytope is a four-dimensional polytope. It is a connected and closed figure, composed of lower-dimensional polytopal elements: vertices, edges, faces (polygons), and cells (polyhedra). Each face is shared by exactly two cells. The 4-polytopes were discovered by the Swiss mathematician Ludwig Schläfli before 1853.
In geometry, the Schläfli symbol is a notation of the form that defines regular polytopes and tessellations.
In geometry, a vertex figure, broadly speaking, is the figure exposed when a corner of a polyhedron or polytope is sliced off.
In geometry, the term semiregular polyhedron is used variously by different authors.
In geometry, a uniform 4-polytope is a 4-dimensional polytope which is vertex-transitive and whose cells are uniform polyhedra, and faces are regular polygons.
In geometry of 4 dimensions or higher, a double prism or duoprism is a polytope resulting from the Cartesian product of two polytopes, each of two dimensions or higher. The Cartesian product of an n-polytope and an m-polytope is an (n+m)-polytope, where n and m are dimensions of 2 (polygon) or higher.
In geometry, a uniform polyhedron has regular polygons as faces and is vertex-transitive. It follows that all vertices are congruent.
In geometry, a pyramid is a polyhedron formed by connecting a polygonal base and a point, called the apex. Each base edge and apex form a triangle, called a lateral face. It is a conic solid with polygonal base. A pyramid with an n-sided base has n + 1 vertices, n + 1 faces, and 2n edges. All pyramids are self-dual.
In geometry, the grand antiprism or pentagonal double antiprismoid is a uniform 4-polytope (4-dimensional uniform polytope) bounded by 320 cells: 20 pentagonal antiprisms, and 300 tetrahedra. It is an anomalous, non-Wythoffian uniform 4-polytope, discovered in 1965 by Conway and Guy. Topologically, under its highest symmetry, the pentagonal antiprisms have D5d symmetry and there are two types of tetrahedra, one with S4 symmetry and one with Cs symmetry.
A dihedron is a type of polyhedron, made of two polygon faces which share the same set of n edges. In three-dimensional Euclidean space, it is degenerate if its faces are flat, while in three-dimensional spherical space, a dihedron with flat faces can be thought of as a lens, an example of which is the fundamental domain of a lens space L(p,q). Dihedra have also been called bihedra, flat polyhedra, or doubly covered polygons.
In geometry, expansion is a polytope operation where facets are separated and moved radially apart, and new facets are formed at separated elements. Equivalently this operation can be imagined by keeping facets in the same position but reducing their size.
In geometry, a skew polygon is a polygon whose vertices are not all coplanar. Skew polygons must have at least four vertices. The interior surface of such a polygon is not uniquely defined.
In geometry, a uniform polytope of dimension three or higher is a vertex-transitive polytope bounded by uniform facets. The uniform polytopes in two dimensions are the regular polygons.
In geometry, a uniform star polyhedron is a self-intersecting uniform polyhedron. They are also sometimes called nonconvex polyhedra to imply self-intersecting. Each polyhedron can contain either star polygon faces, star polygon vertex figures, or both.
In 4-dimensional geometry, a uniform antiprismatic prism or antiduoprism is a uniform 4-polytope with two uniform antiprism cells in two parallel 3-space hyperplanes, connected by uniform prisms cells between pairs of faces. The symmetry of a p-gonal antiprismatic prism is [2p,2+,2], order 8p.
In geometry, a uniform tiling is a tessellation of the plane by regular polygon faces with the restriction of being vertex-transitive.
In geometry, a uniform 5-polytope is a five-dimensional uniform polytope. By definition, a uniform 5-polytope is vertex-transitive and constructed from uniform 4-polytope facets.
In four-dimensional geometry, a prismatic uniform 4-polytope is a uniform 4-polytope with a nonconnected Coxeter diagram symmetry group. These figures are analogous to the set of prisms and antiprism uniform polyhedra, but add a third category called duoprisms, constructed as a product of two regular polygons.