In geometry, the small hexacronic icositetrahedron is the dual of the small cubicuboctahedron. It is visually identical to the small rhombihexacron. A part of each dart lies inside the solid, hence is invisible in solid models.
Proportions Its faces are darts, having two angles of arccos ( 1 4 + 1 2 2 ) ≈ 16.842 116 236 30 ∘ {\displaystyle \arccos({\frac {1}{4}}+{\frac {1}{2}}{\sqrt {2}})\approx 16.842\,116\,236\,30^{\circ }} , one of arccos ( 1 2 − 1 4 2 ) ≈ 81.578 941 881 85 ∘ {\displaystyle \arccos({\frac {1}{2}}-{\frac {1}{4}}{\sqrt {2}})\approx 81.578\,941\,881\,85^{\circ }} and one of 360 ∘ − arccos ( − 1 4 − 1 8 2 ) ≈ 244.736 825 645 55 ∘ {\displaystyle 360^{\circ }-\arccos(-{\frac {1}{4}}-{\frac {1}{8}}{\sqrt {2}})\approx 244.736\,825\,645\,55^{\circ }} . Its dihedral angles equal arccos ( − 7 − 4 2 17 ) ≈ 138.117 959 055 51 ∘ {\displaystyle \arccos({\frac {-7-4{\sqrt {2}}}{17}})\approx 138.117\,959\,055\,51^{\circ }} . The ratio between the lengths of the long edges and the short ones equals 2 − 1 2 2 ≈ 1.292 893 218 81 {\displaystyle 2-{\frac {1}{2}}{\sqrt {2}}\approx 1.292\,893\,218\,81} .
References Wenninger, Magnus (1983), Dual Models, Cambridge University Press, ISBN 978-0-521-54325-5, MR 0730208
External links Weisstein, Eric W., "Small hexacronic icositetrahedron" ("Uniform polyhedron") at MathWorld.




