In geometry, the medial icosacronic hexecontahedron (or midly sagittal ditriacontahedron) is a nonconvex isohedral polyhedron. It is the dual of the uniform icosidodecadodecahedron. Its faces are darts. Part of each dart lies inside the solid, hence is invisible in solid models.
Proportions Faces have two angles of arccos ( 3 4 ) ≈ 41.409 622 109 27 ∘ {\displaystyle \arccos({\frac {3}{4}})\approx 41.409\,622\,109\,27^{\circ }} , one of arccos ( − 1 8 + 7 24 5 ) ≈ 58.184 446 117 59 ∘ {\displaystyle \arccos(-{\frac {1}{8}}+{\frac {7}{24}}{\sqrt {5}})\approx 58.184\,446\,117\,59^{\circ }} and one of 360 ∘ − arccos ( − 1 8 − 7 24 5 ) ≈ 218.996 309 663 87 ∘ {\displaystyle 360^{\circ }-\arccos(-{\frac {1}{8}}-{\frac {7}{24}}{\sqrt {5}})\approx 218.996\,309\,663\,87^{\circ }} . Its dihedral angles equal arccos ( − 5 7 ) ≈ 135.584 691 402 81 ∘ {\displaystyle \arccos(-{\frac {5}{7}})\approx 135.584\,691\,402\,81^{\circ }} . The ratio between the lengths of the long and short edges is 27 + 7 5 22 ≈ 1.938 748 901 93 {\displaystyle {\frac {27+7{\sqrt {5}}}{22}}\approx 1.938\,748\,901\,93} .
References Wenninger, Magnus (1983), Dual Models, Cambridge University Press, ISBN 978-0-521-54325-5, MR 0730208
External links Weisstein, Eric W. "Medial icosacronic hexecontahedron". MathWorld.




