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( ) ∨ s ( ) ∨ (+ ) ( ) ∨ ( 8 |- |bgcolor=#e7dcc3|Faces |colspan=2|20 |- |bgcolor=#e7dcc3|Edges |colspan=2|18 |- |bgcolor=#e7dcc3|Vertices |colspan=2|7 |- |bgcolor=#e7dcc3|Dual |colspan=2|Cubic pyramid |- |bgcolor=#e7dcc3|Symmetry group |colspan=2|B3, (), order 48 (), order 24 (), order 12 (), order 16 (), order 8 |- |bgcolor=#e7dcc3|Properties |colspan=2|convex, regular-faced |} In 4-dimensional geometry, the octahedral pyramid is bounded by one octahedron on the base and 8 triangular pyramid cells which meet at the apex. Since an octahedron has a circumradius divided by edge length less than one,〔 1/sqrt(2) = 0.707107〕 the triangular pyramids can made with regular faces (as regular tetrahedrons) by computing the appropriate height. == Occurrences of the octahedral pyramid== The regular 16-cell has ''octahedral pyramids'' around every vertex, with the octahedron passing through the center of the 16-cell. The octahedral pyramid is the vertex figure for a truncated 5-orthoplex, . :160px 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「Octahedral pyramid」の詳細全文を読む スポンサード リンク
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