雙三角錐

Multi tool use雙三角錐
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 (點選檢視旋轉模型)
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類別 | 雙錐 Johnson多面體 J11 - J12 - J13 |
面 | 6
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邊 | 9
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頂點 | 5
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歐拉特徵數 | F=6, E=9, V=5 (χ=2)
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面的種類 | 三角形
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頂點圖 | V3.4.4
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考克斯特符號 |
    
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對稱群 | D3h, [3,2], (*223) order 12
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對偶 | 三角柱
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旋轉對稱群 | D3, [3,2]+, (223), order 6
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特性 | 凸
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 三角柱 (對偶多面體)
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 (展開圖)
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在幾何學中,雙三角錐是一種基底為三角形的雙錐體,其為三角柱的對偶。若每個面皆為正三角形,則為92種Johnson多面體(J12)中的其中一個,也是雙角錐的其中一種。顧名思義,它可由正多面體中的兩個大小相同的正四面體組合而成。這92種詹森多面體最早在1996年由詹森·諾曼(Norman Johnson)命名並給予描述。
若不考慮每個面皆為正三角形,只考慮基底為正三角形時,則有可能為廣義的半正多面體的對偶,正三角柱的對偶,此時能使用施萊夫例符號表示,計為 + 3,而在考克斯特符號中,則可以用



或表示。
對偶多面體
雙三角錐的對偶多面體是三角柱,但詹森多面體中所描述的雙三角錐其對偶多面體不是一個正三角柱,是一種五面體由三個矩形和二個三角形組成。
雙三角錐的對偶
| 對偶的展開圖
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相關多面體與鑲嵌
雙三角錐可以由三角形二面體透過三角化變換構造而來,因此與三角形二面體具有相同的對稱性,其可以衍生出一些相關的多面體:
半正三角形二面體球面多面體
對稱群:[3,2], (*322)
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3,2
| t3,2
| r3,2
| 2t3,2=t2,3
| 2r3,2=2,3
| rr3,2
| tr3,2
| sr3,2
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半正對偶
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V32
| V62
| V32
| V4.4.3
| V23
| V4.4.3
| V4.4.6
| V3.3.3.3
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半正对偶双棱锥
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作为球面镶嵌
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參見
錐體與柱體
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| 錐體 | |
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| 雙錐體 | - 雙三角錐
- 雙四角錐
- 雙五角錐
- 雙六角錐
- 雙七角錐
- 雙八角錐
- ...
- 雙無限角錐
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| 柱體 | 三角柱 · 四角柱 · 五角柱 · 六角柱 · 七角柱 · 八角柱 · 九角柱 · ... · 無限角柱(雙曲)
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| 反柱體 | 三角反柱 · 四角反柱 · 五角反柱 · 六角反柱 · 七角反柱 · 八角反柱 · ... · 無限角反柱
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| 錐柱體 | 三角錐柱 · 四角錐柱 · 五角錐柱 · 六角錐柱 · 七角錐柱 · 八角錐柱 · ... · 無限角錐柱
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| 其他 | |
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