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|- |bgcolor=#e7dcc3|Edges |colspan=2|12+30 |- |bgcolor=#e7dcc3|Vertices |colspan=2|13 |- |bgcolor=#e7dcc3|Dual |colspan=2|Dodecahedral pyramid |- |bgcolor=#e7dcc3|Symmetry group |colspan=2|H3, (), order 120 |- |bgcolor=#e7dcc3|Properties |colspan=2|convex, regular-faces |} In four-dimensional geometry, the icosahedral pyramid is bounded by one icosahedron on the base and 20 triangular pyramid cells which meet at the apex. Since an icosahedron has a circumradius divided by edge length less than one,〔, circumradius sqrt[(5+sqrt(5))/8 = 0.951057〕 the tetrahedral pyramids can be made with regular faces. The regular 600-cell has icosahedral pyramids around every vertex. The dual to the icosahedral pyramid is the dodecahedral pyramid, seen as a dodecahedral base, and 20 regular pentagonal pyramids meeting at an apex. : == References== 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「icosahedral pyramid」の詳細全文を読む スポンサード リンク
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