File:Academ six unfolded faces dodecahedron.svg

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English: Unfolding of six faces of a platonic dodecahedron, with notations and equalities. KLMNP  is the smallest polygon containing the six unfolded faces. RSUVW is the central face. The side length of all the faces is RS or a, their diagonal length is d or  φ a where φ denotes the golden ratio. G is the common center of KLMNP and RSUVW, which are two convex regular pentagons. The symmetry with respect to G transforms KLMNP into ABCEF. So ALCNFKBMEP is a stellated regular decagon with the same center. Its drawing reveals that of a convex regular decagon with the same center. This convex decagon in thick brown line is the outline of the sheet when folded. We can imagine an animated view of the folding, where RSUVW is fixed, and where a movable vertex of the sheet is depicted by K, which moves on the perpendicular bisector of [UV ]. On this straight line H is a vertex of the decagon, it is the point of arrival of K. On the paths of the images of two movable vertices of the sheet, two arrows are pointing to another point of arrival, another vertex of the decagon, the intersection of (CL ), (FK ) and (EV ).
In this image or in this other one, the outline of the dodecahedron is the same in the top view. The distance between two opposite sides of the outline is the real distance between two opposite edges of the solid, equal to  MN  or  φ d.
Français : Patron de six faces d’un dodécaèdre de Platon, avec des notations et des égalités. KLMNP est le plus petit polygone contenant les six faces dépliées. RSUVW est la face centrale. Toutes les faces ont des côtés de longueur RS ou a, et des diagonales de longueur  d ou  φ a où φ désigne le nombre d’or. G est le centre commun de KLMNP et RSUVW, qui sont deux pentagones réguliers convexes. La symétrie par rapport à G transforme KLMNP en ABCEF. Ainsi ALCNFKBMEP est un décagone régulier étoilé de même centre. Son tracé révèle celui d’un décagone régulier convexe de même centre. Ce décagone convexe en trait brun épais est le contour de la feuille quand elle est pliée. On peut imaginer une vue animée du pliage, où RSUVW est fixe, et où un sommet mobile de la feuille est représenté par K, qui se déplace sur la médiatrice de [UV ]. Sur cette droite H est un sommet du décagone, c’est le point d’arrivée de K. Sur les trajets des images de deux sommets mobiles de la feuille, deux flèches indiquent un autre point d’arrivée, un autre sommet du décagone, l’intersection de (CL ), (FK ) et (EV ).
Dans cette image-ci ou dans cette autre, le contour du dodécaèdre est le même dans la vue de dessus. La distance entre deux côtés opposés du contour est la distance réelle entre deux arêtes opposées du solide, égale à  MN  ou  φ d.
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Author Yves Baelde
SVG development
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Arthur Baelde, the copyright holder of this work, hereby publishes it under the following license:
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Attribution: Arthur Baelde
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Date/TimeThumbnailDimensionsUserComment
current05:39, 30 September 2010Thumbnail for version as of 05:39, 30 September 2010720 × 840 (5 KB)Baelde (talk | contribs)more complete information, with two arrows pointing to a point of arrival on the outline of the sheet when folded
07:01, 4 March 2010Thumbnail for version as of 07:01, 4 March 2010492 × 492 (3 KB)Baelde (talk | contribs)sans spécifier Times en CSS : police non recommandée
15:25, 2 March 2010Thumbnail for version as of 15:25, 2 March 2010512 × 512 (3 KB)Baelde (talk | contribs)To get better PNG images
10:05, 2 March 2010Thumbnail for version as of 10:05, 2 March 2010512 × 512 (3 KB)Baelde (talk | contribs){{Information |Description={{en|1=Bilingual SVG file with 'switch' element: systemLanguage "fr" or "en". <br/>The svg root element has no attribute 'width' or 'height', so that the picture fills the whole width or height of the browser's window.<br/>Unfol

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