|
|- |bgcolor=#e7dcc3|Faces||2''n'' triangles |- |bgcolor=#e7dcc3|Edges||3''n'' |- |bgcolor=#e7dcc3|Vertices||2 + ''n'' |- |bgcolor=#e7dcc3|Face configuration||V4.4.''n'' |- |bgcolor=#e7dcc3|Symmetry group||D''n''h, (), ( *''n''22), order 4''n'' |- |bgcolor=#e7dcc3|Rotation group||D''n'', ()+, (''n''22), order 2''n'' |- |bgcolor=#e7dcc3|Dual polyhedron||''n''-gonal prism |- |bgcolor=#e7dcc3|Properties||convex, face-transitive |- |bgcolor=#e7dcc3|Net|| |} An ''n''-gonal bipyramid or dipyramid is a polyhedron formed by joining an ''n''-gonal pyramid and its mirror image base-to-base. An ''n''-gonal bipyramid has 2''n'' triangle faces, 3''n'' edges, and 2+''n'' vertices. The referenced ''n''-gon in the name of the bipyramids is not an external face but an internal one, existing on the primary symmetry plane which connects the two pyramid halves. ==Right, oblique and concave bipyramids== A right bipyramid has two points above and below the centroid of its base. Nonright bipyramids are called oblique bipyramids. A regular bipyramid has a regular polygon internal face and is usually implied to be a ''right bipyramid''. A right bipyramid can be represented as +P for internal polygon P, and a regular n''-''bipyramid + . A concave bipyramid has a concave interior polygon. :160px The face-transitive regular bipyramids are the dual polyhedra of the uniform prisms and will generally have isosceles triangle faces. A bipyramid can be projected on a sphere or globe as ''n'' equally spaced lines of longitude going from pole to pole, and bisected by a line around the equator. Bipyramid faces, projected as spherical triangles, represent the fundamental domains in the dihedral symmetry Dnh. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bipyramid」の詳細全文を読む スポンサード リンク
|
