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Small Rhombicosidodecahedron


SmallRhombicosidodecahedronSolidWireframeNet

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The (small) rhombicosidodecahedron (Cundy and Rollett 1989, p. 111), sometimes simply called the rhombicosidodecahedron (Wenninger 1989; Maeder 1997; Conway et al. 1999), is the 62-faced Archimedean solid with faces 20{3}+30{4}+12{5}. It is also the uniform polyhedron with Maeder index 27 (Maeder 1997), Wenninger index 14 (Wenninger 1989), Coxeter index 30 (Coxeter et al. 1954), and Har'El index 32 (Har'El 1993). It is illustrated above together with a wireframe version and a net that can be used for its construction.

It has Schläfli symbol r{3; 5} and Wythoff symbol 35|2. The small dodecicosidodecahedron and small rhombidodecahedron are faceted versions.

SmallRhombicosProjections

Some symmetric orthogonal projections of the small rhombicosidodecahedron are illustrated above.

It is implemented in the Wolfram Language as UniformPolyhedron["Rhombicosidodecahedron"]. Precomputed properties are available as PolyhedronData["SmallRhombicosidodecahedron", prop].

SmallRhombicosidodecahedronConvexHulls

The small rhombicosidodecahedron is the convex hull of the small dodecicosidodecahedron, small rhombidodecahedron, and small stellated truncated dodecahedron.

The inradius r_d of the dual polyhedron, midradius rho of the solid and dual polyhedron, and circumradius R of the solid for a=1 are

r_d=1/(41)(15+2sqrt(5))sqrt(11+4sqrt(5))=2.12099...
(1)
rho=1/2sqrt(10+4sqrt(5))=2.17625...
(2)
R=1/2sqrt(11+4sqrt(5))=2.23295....
(3)

The unit small rhombicosidodecahedron has surface area

 S=5(6+sqrt(3))+3·5^(3/4)sqrt(2+sqrt(5))
(4)

and volume

 V=1/3(60+29sqrt(5)).
(5)

The Dehn invariant of the unit small rhombicosidodecahedron has the following representative in the basis of Conway et al. (1999):

D=60<3>_5-30<5>_1
(6)
=30sin^(-1)((5-4sqrt(5))/(15))
(7)
=-7.98240....
(8)

The decimal expansion of -D is given by OEIS A377606. The small rhombicosidodecahedron can be dissected into the metabigyrate rhombicosidodecahedron, parabigyrate rhombicosidodecahedron, and trigyrate rhombicosidodecahedron, from which it differs only by the relative rotations of two or three cupolae.

SmallRhombicosidodecahedronAndDual

The dual polyhedron of the small rhombicosidodecahedron is the deltoidal hexecontahedron, both of which are illustrated above together with their common midsphere.

SmallRhombicosidodecahedronMinkowskiSum

The Minkowski sum of a unit regular dodecahedron and unit regular icosahedron in dual position is a small rhombicosidodecahedron.

Hervay (2026) gives a computer-assisted proof that the small rhombicosidodecahedron is a nopert polyhedron, meaning that it does not have Rupert's property. This settles the conjecture of Steininger and Yurkevich (2023) and gives the first Archimedean solid proved not to have the property. The proof covers the symmetry-reduced configuration space with 192696 regions verified using exact arithmetic in Q(sqrt(5)). Its Nieuwland number is therefore 1.


See also

Archimedean Solid, Equilateral Zonohedron, Great Rhombicosidodecahedron, Hexecontahedron, Nieuwland Number, Nopert Polyhedron, Quasirhombicosidodecahedron, Rhombicosidodecahedron, Rupert's Property, Zome

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References

Conway, J. H.; Radin, C.; and Sadun, L. "On Angles Whose Squared Trigonometric Functions Are Rational." Discr. Computat. Geom. 22, 321-332, 1999.Coxeter, H. S. M.; Longuet-Higgins, M. S.; and Miller, J. C. P. "Uniform Polyhedra." Phil. Trans. Roy. Soc. London Ser. A 246, 401-450, 1954.Cundy, H. and Rollett, A. "(Small) Rhombicosidodecahedron. 3.4.5.4." §3.7.11 in Mathematical Models, 3rd ed. Stradbroke, England: Tarquin Pub., p. 111, 1989.Har'El, Z. "Uniform Solution for Uniform Polyhedra." Geometriae Dedicata 47, 57-110, 1993.Hervay, B. "Non-Rupertness of the Rhombicosidodecahedron." Preprint. https://doi.org/10.5281/zenodo.23013945. 28 Sep 2026.Kasahara, K. "From Regular to Semiregular Polyhedrons." Origami Omnibus: Paper-Folding for Everyone. Tokyo, Japan: Japan Publications, pp. 220-221, 1988.Maeder, R. E. "27: Rhombicosidodecahedron." 1997. https://www.mathconsult.ch/static/unipoly/27.html.McCooey, D. I. "Rhombicosidodecahedron." https://dmccooey.com/polyhedra/Rhombicosidodecahedron.html.Sloane, N. J. A. Sequence A377606 in "The On-Line Encyclopedia of Integer Sequences."Steininger, J. and Yurkevich, S. "An Algorithmic Approach to Rupert's Problem." Math. Comput. 92, 1905-1929, 2023. https://doi.org/10.1090/mcom/3831.Wenninger, M. J. "The Rhombicosidodecahedron." Model 14 in Polyhedron Models. Cambridge, England: Cambridge University Press, p. 28, 1989.

Referenced on Wolfram|Alpha

Small Rhombicosidodecahedron

Cite this as:

Weisstein, Eric W. "Small Rhombicosidodecahedron." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/SmallRhombicosidodecahedron.html

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