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[几何] 正五边形外接圆半径

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hbghlyj posted 2024-4-18 02:06 |Read mode

正二十面體中，M、N是正五邊形的中心，則MN=MI

YF1N9[1].png

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original poster hbghlyj posted 2024-4-18 02:12

Equiangular lines in Euclidean space

The maximum in 3 dimensions is 6: we can take lines through opposite vertices of an icosahedron.

OA、OB、OC、OD、OE、OF两两夹角相等

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