Rhombic triacontahedron

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Rhombic triacontahedron
Rhombic triacontahedron
(Click here for rotating model)
Type Catalan solid
Coxeter diagram CDel node.pngCDel 5.pngCDel node f1.pngCDel 3.pngCDel node.png
Conway notation jD
Face type V3.5.3.5
DU24 facets.png

rhombus
Faces 30
Edges 60
Vertices 32
Vertices by type 20{3}+12{5}
Symmetry group Ih, H3, [5,3], (*532)
Rotation group I, [5,3]+, (532)
Dihedral angle 144°
Properties convex, face-transitive edge-transitive, zonohedron
Icosidodecahedron.svg
Icosidodecahedron
(dual polyhedron)
Rhombic triacontahedron Net
Net

In geometry, the rhombic triacontahedron is a convex polyhedron with 30 rhombic faces. It has 60 edges and 32 vertices of two types. It is a Catalan solid, and the dual polyhedron of the icosidodecahedron. It is a zonohedron.

GoldenRhombus.svg
A face of the rhombic triacontahedron. The lengths
of the diagonals are in the golden ratio.

The ratio of the long diagonal to the short diagonal of each face is exactly equal to the golden ratio, φ, so that the acute angles on each face measure 2 tan−1(1/φ) = tan−1(2), or approximately 63.43°. A rhombus so obtained is called a golden rhombus.

Being the dual of an Archimedean solid, the rhombic triacontahedron is face-transitive, meaning the symmetry group of the solid acts transitively on the set of faces. This means that for any two faces, A and B, there is a rotation or reflection of the solid that leaves it occupying the same region of space while moving face A to face B.

The rhombic triacontahedron is somewhat special in being one of the nine edge-transitive convex polyhedra, the others being the five Platonic solids, the cuboctahedron, the icosidodecahedron, and the rhombic dodecahedron.

The rhombic triacontahedron is also interesting in that its vertices includes the arrangmenmt of all the platonic solids. It contains ten tetrahedrons, five hexahedrons, five octahedrons, an icosahedron and a dodecahedron.

Dimensions[edit]

If the edge length of a rhombic triacontahedron is a, surface area, volume, the radius of an inscribed sphere (tangent to each of the rhombic triacontahedron's faces) and midradius, which touches the middle of each edge are:[1]

S = a^2 \cdot 12\sqrt{5} \approx 26.8328 \cdot a^2

V = a^3 \cdot 4\sqrt{5+2\sqrt{5}} \approx 12.3107 \cdot a^3

r_i = a \cdot \frac{\varphi^2}{\sqrt{1 + \varphi^2}} = a \cdot \sqrt{1 + \frac{2}{\sqrt{5}}} \approx 1.37638 \cdot a

r_m = a \cdot \left(1+\frac{1}{\sqrt5{}}\right) \approx 1.44721 \cdot a

where φ is the golden ratio.

The plane of each face is perpendicular to the center of the rhombic triacontahedron, and is located at the same distance (short diagonals belong only to the edges of the inscribed regular dodecahedron, while long diagonals are included only in edges of the inscribed icosahedron). Using one of the three orthogonal golden rectangles drawn into the inscribed icosahedron we can easily deduce the distance between the center of the solid and the center of its rhombic face.

Uses of rhombic triacontahedra[edit]

Danish designer Holger Strøm used the rhombic triacontahedron as a basis for the design of his buildable lamp IQ-light. (IQ for "Interlocking Quadrilaterals")

An example of the use of a rhombic triacontahedron in the design of a lamp. IQ stands for “Interlocking Quadrilaterals”.

Woodworker Jane Kostick builds boxes in the shape of a rhombic triacontahedron.[2] The simple construction is based on the less than obvious relationship between the rhombic triacontahedron and the cube.

Roger von Oech's "Ball of Whacks" comes in the shape of a rhombic triacontahedron.

In some roleplaying games, and for elementary school uses, the rhombic triacontahedron is used as the "d30" thirty-sided die.

Related polyhedra[edit]

Family of uniform icosahedral polyhedra
Symmetry: [5,3], (*532) [5,3]+, (532)
CDel node 1.pngCDel 5.pngCDel node.pngCDel 3.pngCDel node.png CDel node 1.pngCDel 5.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 5.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 5.pngCDel node 1.pngCDel 3.pngCDel node 1.png CDel node.pngCDel 5.pngCDel node.pngCDel 3.pngCDel node 1.png CDel node 1.pngCDel 5.pngCDel node.pngCDel 3.pngCDel node 1.png CDel node 1.pngCDel 5.pngCDel node 1.pngCDel 3.pngCDel node 1.png CDel node h.pngCDel 5.pngCDel node h.pngCDel 3.pngCDel node h.png
Uniform polyhedron-53-t0.png Uniform polyhedron-53-t01.png Uniform polyhedron-53-t1.png Uniform polyhedron-53-t12.png Uniform polyhedron-53-t2.png Uniform polyhedron-53-t02.png Uniform polyhedron-53-t012.png Uniform polyhedron-53-s012.png
{5,3} t{5,3} r{5,3} 2t{5,3}=t{3,5} 2r{5,3}={3,5} rr{5,3} tr{5,3} sr{5,3}
Duals to uniform polyhedra
CDel node f1.pngCDel 5.pngCDel node.pngCDel 3.pngCDel node.png CDel node f1.pngCDel 5.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel 5.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel 5.pngCDel node f1.pngCDel 3.pngCDel node f1.png CDel node.pngCDel 5.pngCDel node.pngCDel 3.pngCDel node f1.png CDel node f1.pngCDel 5.pngCDel node.pngCDel 3.pngCDel node f1.png CDel node f1.pngCDel 5.pngCDel node f1.pngCDel 3.pngCDel node f1.png CDel node fh.pngCDel 5.pngCDel node fh.pngCDel 3.pngCDel node fh.png
Icosahedron.svg Triakisicosahedron.jpg Rhombictriacontahedron.svg Pentakisdodecahedron.jpg POV-Ray-Dodecahedron.svg Deltoidalhexecontahedron.jpg Disdyakistriacontahedron.jpg Pentagonalhexecontahedronccw.jpg
V5.5.5 V3.10.10 V3.5.3.5 V5.6.6 V3.3.3.3.3 V3.4.5.4 V4.6.10 V3.3.3.3.5

This polyhedron is a part of a sequence of rhombic polyhedra and tilings with [n,3] Coxeter group symmetry. The cube can be seen as a rhombic hexahedron where the rhombi are also rectangles.

Dimensional family of quasiregular polyhedra and tilings: 3.n.3.n
Symmetry
*n32
[n,3]
Spherical Euclidean Compact hyperbolic Paracompact Noncompact
*332
[3,3]
Td
*432
[4,3]
Oh
*532
[5,3]
Ih
*632
[6,3]
p6m
*732
[7,3]
*832
[8,3]...
*∞32
[∞,3]
 
[iπ/λ,3]
Quasiregular
figures
configuration
Uniform tiling 332-t1-1-.png
3.3.3.3
Uniform tiling 432-t1.png
3.4.3.4
Uniform tiling 532-t1.png
3.5.3.5
Uniform tiling 63-t1.png
3.6.3.6
Uniform tiling 73-t1.png
3.7.3.7
Uniform tiling 83-t1.png
3.8.3.8
H2 tiling 23i-2.png
3.∞.3.∞
3.∞.3.∞
Coxeter diagram CDel node.pngCDel 3.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 4.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 5.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 6.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 7.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 8.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel infin.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel ultra.pngCDel node 1.pngCDel 3.pngCDel node.png
Dual
(rhombic)
figures
configuration
Hexahedron.svg
V3.3.3.3
Rhombicdodecahedron.jpg
V3.4.3.4
Rhombictriacontahedron.svg
V3.5.3.5
Rhombic star tiling.png
V3.6.3.6
Order73 qreg rhombic til.png
V3.7.3.7
Uniform dual tiling 433-t01-yellow.png
V3.8.3.8
Ord3infin qreg rhombic til.png
V3.∞.3.∞
Coxeter diagram CDel node.pngCDel 3.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel 4.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel 5.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel 6.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel 7.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel 8.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel infin.pngCDel node f1.pngCDel 3.pngCDel node.png CDel node.pngCDel ultra.pngCDel node f1.pngCDel 3.pngCDel node.png

The rhombic triacontahedron forms the convex hull of one projection of a 6-cube to 3 dimensions.

A rhombic triacontahedron with an inscribed tetrahedron (red) and cube (yellow).
(Click here for rotating model)
A rhombic triacontahedron with an inscribed dodecahedron (blue) and icosahedron (purple).
(Click here for rotating model)
6Cube-QuasiCrystal.jpg
The 3D basis vectors [u,v,w] are:
u = (1, φ, 0, -1, φ, 0)
v = (φ, 0, 1, φ, 0, -1)
w = (0, 1, φ, 0, -1, φ)
RhombicTricontrahedron.png
Shown with inner edges hidden
There are 64 vertices and 192 unit length edges forming pentagonal symmetry along specific axis (as well as hexagonal symmetries on other axis).

Stellations[edit]

The rhombic triacontahedron has over 227 stellations.[3][4]

See also[edit]

References[edit]

  1. ^ Stephen Wolfram, "[1]" from Wolfram Alpha. Retrieved January 7, 2013.
  2. ^ triacontahedron box - KO Sticks LLC
  3. ^ Pawley, G. S. (1975). "The 227 triacontahedra". Geometriae Dedicata (Kluwer Academic Publishers) 4 (2-4): 221–232. doi:10.1007/BF00148756. ISSN 1572-9168. 
  4. ^ Messer, P. W. (1995). "Stellations of the Rhombic Triacontahedron and Beyond". Structural Topology 21: 25–46. 

External links[edit]