Vertices: | 10 (10[4]) |
Faces: | 12 (10 equilateral triangles + 2 regular pentagrams) |
Edges: | 20 |
Symmetry: | 5-fold Antiprismatic (D5v) |
Pentagram-Triangle Angle: | acos(sqrt(15*(5+2*sqrt(5)))/15) | ≈37.377368141 degrees |
Triangle-Triangle Angle: | acos(sqrt(5)/3) | ≈318.189685104 degrees |
Dual Solid: | Pentagrammic Concave Trapezohedron |
(values below based on edge length = 1) |
Circumscribed Radius: | sqrt(2*(5−sqrt(5)))/4 | ≈0.58778525229247312917 |
Midscribed Radius: | (sqrt(5)−1)/4 | ≈0.30901699437494742410 |
Pentagram Center Radius: | sqrt(10*(5−sqrt(5)))/20 | ≈0.26286555605956680301 |
Triangle Center Radius: | −(3*sqrt(3)−sqrt(15))/12 | ≈−0.11026408970826791628 |
References: | [1] | Jean Paul Albert Badoureau, Mémoire sur les Figures Isocèles, Journal de l'École polytechnique 49 (1881), 47-172. |
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