Talk:Rhombicosidodecahedron

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I believe the Dihedral angle should read 148.28˚ (pentagon-square) and 159.1˚ (triangle-square) I couldn't figure out how to edit that field. — Preceding unsigned comment added by Lemonnn (talk • contribs) 07:23, 15 March 2012 (UTC)

Should there perhaps be a volume formula? WolframAlpha says it's Volume = (20 + (29√5) / 3)(edge^3), and after an afternoon of scribbling, I can corroborate that the math checks out. — Preceding unsigned comment added by BassKMB (talk • contribs) 05:11, 24 November 2011 (UTC)

Schläfli symbol is wrong. It should be:

$r\left\lbrace {\frac {3}{5}}\right\rbrace$

Robert Stanforth 17:57, 9 January 2007 (UTC)

now fixed Robert Stanforth 19:24, 9 January 2007 (UTC)

There shouldn't be a fraction bar. Professor M. Fiendish, Esq. 08:04, 23 August 2009 (UTC)

Acknowledged - aware it should be $r{\begin{Bmatrix}3\\5\end{Bmatrix}}$ - but I was new to the maths markup syntax at the time! Robert Stanforth (talk) 23:16, 25 August 2009 (UTC)

Kids at St. Germaine School

For the last 12 months, an anonymous user, Special:Contributions/71.60.211.222, has been dropping in variations on this paragraph and revert repeated. Such persistence! Tom Ruen (talk) 22:14, 15 February 2008 (UTC)

DO NOT DELETE:

Kids at St. Germaine School in Bethel Park, PA built the worlds largest rhombicosidodecahedron, which stood at over 9 feet tall. The workers included, but are certainly not limited to (in alphabetical order) Bridget Bielich, Callie Hanua, Glenn Huetter, Carl Mitchell, Anthony "TJ" Serafini, and Leanna Talarico. Bielich's grandfather, Walter, donated the cardboard for the project. The shape stood on its own, although for several weeks it sat in a cold convent, haunted by dead nuns and supported by chairs. It was painted blue, purple, and pink. The building of the shape caused great unity among the 8th grade class, and it also took up a lot of math class time. The record-breaking construction was written about in the Post-Gazette.

It is annonying for sure - I have actually found the link http://www.post-gazette.com/pg/04063/280160-55.stm - The Pittsburgh Post Gazette copy reads a lot better than Kids at St. Germaine School in..... Indeed such persistence is disruptive.

The easiest solution, other than waste time reverting edits all evening is to request a block now and again at Administrator Intervention against Vandalism, after a couple of blocks such persistence may wane (or collapse like said St Germaine's school rhombicosidodecahedron).

This is in reply to your query at Editor Assistance/Requests. -- BpEps - t@lk 06:27, 29 February 2008 (UTC)

It strikes me that it would be reasonable to include a picture of the model, with a brief caption. —Tamfang (talk) 17:03, 15 March 2008 (UTC)

It looks just like . Professor M. Fiendish, Esq. 05:45, 29 August 2009 (UTC)

Same colors and everything? —Tamfang (talk) 19:09, 29 August 2009 (UTC)

Uh, not the same colours. You can see an image on the webpage. Let's just hope it doesn't collapse. Professor M. Fiendish, Esq. 05:26, 2 September 2009 (UTC)

I think that would make an excellent contribution to this article. Just, is the news a reliable source? —The Doctahedron, 68.173.113.106 (talk) 22:56, 24 November 2011 (UTC)

Pseudo version?

Since there's a pseudo version of the rhombicuboctahedron, what about the rhombicosidodecahedron?

• 
  Rhombicuboctahedron
• 
  Pseudorhombicuboctahedron
• 
  Rhombicosidodecahedron
• 
  Pseudorhombicosidodecahedron?

Professor M. Fiendish, Esq. 05:29, 2 September 2009 (UTC)

There's a few, like Gyrate rhombicosidodecahedron, but vertex configurations change order on some vertices, from 3.4.5.4 to 3.4.4.5. Tom Ruen (talk) 06:08, 2 September 2009 (UTC)

Free 3D object

Hello, the possibility to have all these objects in a free format will be very great ! (collada ? ) —Preceding unsigned comment added by 132.167.34.39 (talk) 09:01, 29 September 2009 (UTC)

If you mean 3D data, the MathWorld 3d animations have datafiles you can extract with a bit of work:[1]. There's also VRML data at Hart's website: [2]. Tom Ruen (talk) 02:48, 30 September 2009 (UTC)

Expansion animation

Personally, I think the second animation is smoother, and therefore better, than the first one. —The Doctahedron, 68.173.113.106 (talk) 22:59, 24 November 2011 (UTC)

The meaning and origin of "rhombi-"

On several Wikipedia pages, regarding the naming of solids, it is claimed—in all instances, without citation—that the prefix "rhombi-" comes from the fact that some or all of the faces of the solid in question lie in the same plane as the faces of another solid (e.g., the rhombic dodecahedron) that happens to have the name "rhombic" in it. I think this can be shown to be specious (even though I've found this claim on one non-Wikipedia page, but also unsourced there) for several reasons:

(1) See http://www.geom.uiuc.edu/~teach95/kt95/KTL12t.html. This page says, "What does rhombi mean in the name of a polyhedron? Answer: The true answer to this is a bit complex. Students should make a connection between the red (medium shaded) squares that arise in the polyhedra with rhombi in the naming. You could make the connection that the etymology of rhombi meant a square."

(2) The most obvious meaning of "rhomb-" is related to squares or rhombuses (rhombi). All the polyhedra with "rhomb-" prefixes have square faces. (And there's something special about them, which I'll explain later.)

(3) An alternate name for the cuboctahedron is "rhombitetratetrahedron," but the cuboctahedron does not have any set of faces that happen to lie in the same plane as another solid with "rhombic" in its name.

(4) I'm guessing (but can't source this) that many of the "rhombi-" names were in use BEFORE the names of the solids that supposedly gave rise to their "rhomb-" prefixes.

(5) A logical explanation (hinted at in the above link) is that the square faces came as the result of distortion into a "rhombic" shape (i.e., their square shape, which are quadrilaterals with equal-length sides) after the solid was generated by a geometric operation, such as expansion. For example, the rhombi-truncated cuboctahedron is generated by truncation of the cuboctahedron, but this leaves rectangles instead of square faces. The "rhombi-" prefix clarifies that the truncated shape must be deformed into the Archimedean solid that has square faces instead of rectangles. You can easily find an explanation like this for all solids that have "rhomb" in their names or alternate names.

(6) It just seems odd that the coincidence of planes for some faces should justify a name, when there's often no other direct connection to the named-after solid, especially when there are usually many other solids with closer geometrical connections that did not affect the naming of the new solid. For example, there are many solids that have faces that lie in the same plane as dodecahedra (or tetrahedra, or cubes), yet they don't have some form or portion of the word "dodecahedron" (or "tetrahedron," or "cube") in their name. If anyone can confirm the information as written, please do so. Otherwise, I may change the text and cite the link I have provided above.Holy (talk) 01:22, 24 February 2017 (UTC)