{"id":3745,"date":"2022-09-26T15:51:53","date_gmt":"2022-09-26T13:51:53","guid":{"rendered":"https:\/\/erlebnisland-mathematik.de\/?page_id=3745"},"modified":"2023-06-21T15:02:28","modified_gmt":"2023-06-21T13:02:28","slug":"advanced-text-polyhedral-crown-platonic-solids","status":"publish","type":"page","link":"https:\/\/erlebnisland-mathematik.de\/en\/advanced-text-polyhedral-crown-platonic-solids\/","title":{"rendered":"Advanced Text Polyhedral Crown (Platonic Solids)"},"content":{"rendered":"<div class=\"wpb-content-wrapper\"><p>[vc_row drowwidth=&#8221;sidebar-biest-default sidebar-biest&#8221;][vc_column][vc_column_text]<\/p>\n<h1>Platonic bodies<\/h1>\n<p> <em>Platonic<\/em> solids (or: <em>ideal solids<\/em>, <em>regular polyhedra<\/em> &#8212; &#8220;<em>polyhedra<\/em>&#8220;) are <em>convex<\/em> solids with the greatest possible regularity, named after the Greek philosopher <em>Plato<\/em> (427&#8211;347 BC). (Here a body is called <em>convex<\/em> if with two each of its points <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-abc95366fcad467cee6b50cb061004c3_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#80;\" title=\"Rendered by QuickLaTeX.com\" height=\"13\" width=\"12\" style=\"vertical-align: 0px;\"\/> and <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-56d41c25943edffa475002a035e854bc_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#81;\" title=\"Rendered by QuickLaTeX.com\" height=\"15\" width=\"12\" style=\"vertical-align: -2px;\"\/> also all points on the connecting line <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-6ab51eaeda7aaea9688706556097baad_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#92;&#111;&#118;&#101;&#114;&#108;&#105;&#110;&#101;&#123;&#80;&#81;&#125;\" title=\"Rendered by QuickLaTeX.com\" height=\"17\" width=\"26\" style=\"vertical-align: -2px;\"\/> belong to it).<\/p>\n<p>This (&#8220;<em>greatest possible<\/em>&#8220;) regularity consists in the fact that for each of these solids all side faces are <em>congruent<\/em> (&#8220;congruent&#8221;) to each other and that they meet in the same way in each corner.<\/p>\n<p>There are exactly five Platonic bodies:[\/vc_column_text][vc_single_image image=&#8221;2394&#8243; img_size=&#8221;large&#8221; alignment=&#8221;center&#8221;]Figure 1: The Five Platonic Bodies[\/vc_single_image][vc_column_text]Specifically, these five bodies have the following properties:<\/p>\n\n<table id=\"tablepress-44\" class=\"tablepress tablepress-id-44 tablepress-responsive\">\n<thead>\n<tr class=\"row-1\">\n\t<th class=\"column-1\"><\/th><th class=\"column-2\">Side faces<\/th><th class=\"column-3\">Number of faces<\/th><th class=\"column-4\">Number of corners<\/th><th class=\"column-5\">Number of edges<\/th><th class=\"column-6\">Number of faces in a corner<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr class=\"row-2\">\n\t<td class=\"column-1\">Tetrahedron<\/td><td class=\"column-2\">equilateral triangle<\/td><td class=\"column-3\">4<\/td><td class=\"column-4\">4<\/td><td class=\"column-5\">6<\/td><td class=\"column-6\">3<\/td>\n<\/tr>\n<tr class=\"row-3\">\n\t<td class=\"column-1\">Cube (Hex- ameter)<\/td><td class=\"column-2\">squares<\/td><td class=\"column-3\">6<\/td><td class=\"column-4\">8<\/td><td class=\"column-5\">12<\/td><td class=\"column-6\">3<\/td>\n<\/tr>\n<tr class=\"row-4\">\n\t<td class=\"column-1\">Octahedron<\/td><td class=\"column-2\">equilateral triangle<\/td><td class=\"column-3\">8<\/td><td class=\"column-4\">6<\/td><td class=\"column-5\">12<\/td><td class=\"column-6\">4<\/td>\n<\/tr>\n<tr class=\"row-5\">\n\t<td class=\"column-1\">Dodecahedron<\/td><td class=\"column-2\">regular pentagons<\/td><td class=\"column-3\">12<\/td><td class=\"column-4\">20<\/td><td class=\"column-5\">30<\/td><td class=\"column-6\">3<\/td>\n<\/tr>\n<tr class=\"row-6\">\n\t<td class=\"column-1\">Icosahedron<\/td><td class=\"column-2\">equilateral triangles<\/td><td class=\"column-3\">20<\/td><td class=\"column-4\">12<\/td><td class=\"column-5\">30<\/td><td class=\"column-6\">5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<!-- #tablepress-44 from cache -->\n<p style=\"text-align: center;\">Figure 1: The properties of the five Platonic solids<\/p>\n<p>[\/vc_column_text][vc_column_text]The Platonic Bodies have played a significant role in intellectual history from ancient Greece through the Middle Ages to our own time. <em>Tetrahedron<\/em>, <em>hexahedron<\/em> (cube) and <em>dodecahedron<\/em> were well known to the students of Pythagoras in the 6th century BC. <em>Theaitetos<\/em> (4th century BC) was also familiar with <em>octahedron<\/em> and <em>icosahedron<\/em>.<\/p>\n<p>Platon has described the solids, which were named after him later, in his work <em>Timaisos<\/em> detailed and assigned to them the four elements, which were according to the opinion at this time the &#8220;<em>World building blocks<\/em>&#8220;, in the following way:<\/p>\n<ul>\n<li>Tetrahedron &#8212; Fire;<\/li>\n<li>Hexahedron (cube) &#8212; Earth;<\/li>\n<li>Octahedron &#8212; Air;<\/li>\n<li>Icosahedron &#8212; water.<\/li>\n<\/ul>\n<p>The later added fifth element &#8220;<em>ether<\/em>&#8221; (which was interpreted as &#8220;<em>upper heaven<\/em>&#8221; in antiquity and whose existence played a special role in physics until the 19th century) was assigned to the dodecahedron.<\/p>\n<p>Famous is also the attempt of the astronomer <em>Johannes Kepler<\/em> (1571&#8211;1630), in 1596 in his work <em>Mysterium Cosmographicum<\/em>, to describe the (mean) orbital radii of the six planets known at that time (<em>Mercury<\/em>, <em>Venus<\/em>, <em>Earth<\/em>, <em>Mars<\/em>, <em>Jupiter<\/em>, <em>Saturn<\/em>) by a certain sequence of the five Platonic solids and their inner and outer spheres:[\/vc_column_text][vc_single_image image=&#8221;2398&#8243; img_size=&#8221;large&#8221; alignment=&#8221;center&#8221;]Figure 2: Model of the solar system in Kepler&#8217;s Mysterium Cosmographicum (1596).[\/vc_single_image][vc_column_text]<\/p>\n<h3>And now &#8230; the mathematics:<\/h3>\n<p>[\/vc_column_text][vc_column_text]Already <em>Euclid<\/em> (about 300 BC) proved in his famous work <em>The Elements<\/em> that there are exactly five of these Platonic solids.<\/p>\n<p>The following considerations lead to this:<\/p>\n<p>The sum of the interior angles in an <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-8ad02d5f0d297c7adacb6b8c4f9fee74_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"8\" style=\"vertical-align: 0px;\"\/>-corner is <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-30de09d4fc72b9c2bbb9b10b73d84e25_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#40;&#110;&#45;&#49;&#41;&#92;&#99;&#100;&#111;&#116;&#49;&#56;&#48;&#94;&#92;&#99;&#105;&#114;&#99;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"100\" style=\"vertical-align: -5px;\"\/>. So every interior angle in a regular <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-8ad02d5f0d297c7adacb6b8c4f9fee74_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"8\" style=\"vertical-align: 0px;\"\/>-corner has the value <\/p>\n<p class=\"ql-center-displayed-equation\" style=\"line-height: 36px;\"><span class=\"ql-right-eqno\"> &nbsp; <\/span><span class=\"ql-left-eqno\"> &nbsp; <\/span><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-811f3d3684ce293727582e5daf3c1390_l3.png\" height=\"36\" width=\"93\" class=\"ql-img-displayed-equation quicklatex-auto-format\" alt=\"&#92;&#091;&#92;&#102;&#114;&#97;&#99;&#123;&#110;&#45;&#50;&#125;&#123;&#110;&#125;&#92;&#99;&#100;&#111;&#116;&#32;&#49;&#56;&#48;&#94;&#92;&#99;&#105;&#114;&#99;&#46;&#92;&#093;\" title=\"Rendered by QuickLaTeX.com\"\/><\/p>\n<p>(e.g. for an equilateral triangle 60\u00b0, for a square 90\u00b0, for a regular pentagon 108\u00b0, etc.)<\/p>\n<p>If <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-be9a75538a40c1b875b526b17ab74e1f_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"13\" style=\"vertical-align: 0px;\"\/> denotes the number of faces meeting in a corner of the Platonic solid, the sum of their angles must be less than 360\u00b0, i.e. <\/p>\n<p class=\"ql-center-displayed-equation\" style=\"line-height: 36px;\"><span class=\"ql-right-eqno\"> &nbsp; <\/span><span class=\"ql-left-eqno\"> &nbsp; <\/span><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-1468efa46550bc51aedcbb1c12fe6294_l3.png\" height=\"36\" width=\"179\" class=\"ql-img-displayed-equation quicklatex-auto-format\" alt=\"&#92;&#091;&#109;&#92;&#99;&#100;&#111;&#116;&#92;&#102;&#114;&#97;&#99;&#123;&#110;&#45;&#50;&#125;&#123;&#110;&#125;&#92;&#99;&#100;&#111;&#116;&#32;&#49;&#56;&#48;&#94;&#92;&#99;&#105;&#114;&#99;&#60;&#51;&#54;&#48;&#94;&#92;&#99;&#105;&#114;&#99;&#46;&#92;&#093;\" title=\"Rendered by QuickLaTeX.com\"\/><\/p>\n<p>From this now follows <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-6a0fa31dec7b87df1f3fba6f66bb7f82_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;&#40;&#110;&#45;&#50;&#41;&#60;&#50;&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"109\" style=\"vertical-align: -5px;\"\/>, which we further convert to <\/p>\n<p class=\"ql-center-displayed-equation\" style=\"line-height: 19px;\"><span class=\"ql-right-eqno\"> &nbsp; <\/span><span class=\"ql-left-eqno\"> &nbsp; <\/span><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-c9fb629af7f97cf8efe0412903eaf720_l3.png\" height=\"19\" width=\"196\" class=\"ql-img-displayed-equation quicklatex-auto-format\" alt=\"&#92;&#091;&#40;&#109;&#45;&#50;&#41;&#92;&#99;&#100;&#111;&#116;&#40;&#110;&#45;&#50;&#41;&#60;&#52;&#92;&#113;&#117;&#97;&#100;&#32;&#40;&#92;&#97;&#115;&#116;&#41;&#92;&#093;\" title=\"Rendered by QuickLaTeX.com\"\/><\/p>\n<p>change over.<\/p>\n<p>Now, since <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-27adcd93af9c171286bb7ea8e310b734_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;&#62;&#50;\" title=\"Rendered by QuickLaTeX.com\" height=\"14\" width=\"45\" style=\"vertical-align: -2px;\"\/> (each of the bounding faces has at least three corners) and <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-27adcd93af9c171286bb7ea8e310b734_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;&#62;&#50;\" title=\"Rendered by QuickLaTeX.com\" height=\"14\" width=\"45\" style=\"vertical-align: -2px;\"\/> (at least three faces meet in each corner of the body), only the following five pairs <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-06dba666d1d18d7a5434ad3be2a4ed84_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#40;&#109;&#44;&#32;&#110;&#41;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"44\" style=\"vertical-align: -5px;\"\/> of natural numbers (each greater than 2) satisfy the inequality <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-168bf84c8662e499050a4b9df1904cde_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#40;&#92;&#97;&#115;&#116;&#41;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"21\" style=\"vertical-align: -5px;\"\/>:<\/p>\n<ul>\n<li><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-27cf5f442b67719b98059c86c2bc1c36_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#40;&#51;&#44;&#51;&#41;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"38\" style=\"vertical-align: -5px;\"\/> &#8212; tetrahedron;<\/li>\n<li><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-a6c7af3a1be501b386ec03c4e28d29ec_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#40;&#52;&#44;&#51;&#41;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"38\" style=\"vertical-align: -5px;\"\/> &#8212; octahedron;<\/li>\n<li><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-fd4893a2090a714099bd668ddf417691_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#40;&#53;&#44;&#51;&#41;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"38\" style=\"vertical-align: -5px;\"\/> &#8212; icosahedron;<\/li>\n<li><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-1cfd45a76ced41105e7a4909cdd078bd_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#40;&#51;&#44;&#52;&#41;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"38\" style=\"vertical-align: -5px;\"\/> &#8212; cube;<\/li>\n<li><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/erlebnisland-mathematik.de\/wp-content\/ql-cache\/quicklatex.com-a9626987ce7814b977c21b05c3eb2d19_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#40;&#51;&#44;&#53;&#41;\" title=\"Rendered by QuickLaTeX.com\" height=\"19\" width=\"38\" style=\"vertical-align: -5px;\"\/> &#8212; dodecahedron.<\/li>\n<\/ul>\n<p>This ends the proof.[\/vc_column_text][vc_column_text]<\/p>\n<h3>Literature<\/h3>\n<p>[\/vc_column_text][vc_column_text][1] Adam, P. and Wyss, A.:<em>Platonic and Archimedean solids, their stellar and polar forms<\/em>, Stuttgart, 1994.<\/p>\n<p>[2] Beutelspacher, A. u.a.:<em>Mathematik zum Anfassen<\/em>, Mathematikum, Gie\u00dfen, 2005.<\/p>\n<p>[3] Euclid: <em>The Elements, Book XIII<\/em>, ed. u. \u00fcbs. v. Clemens Thaer, 4. Auflage, Frankfurt am Main, 2003.<\/p>\n<p>[4] Kepler, J.: <em>Mysterium cosmographicum. De stella nova, <\/em>Hrsg. Max Caspar, M\u00fcnchen, 1938.<\/p>\n<p>[5] Tiberiu, R.: <em>Regul\u00e4re und halbregul\u00e4re Polyeder<\/em>, Berlin, 1987.[\/vc_column_text][\/vc_column][\/vc_row]<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>[vc_row drowwidth=&#8221;sidebar-biest-default sidebar-biest&#8221;][vc_column][vc_column_text] Platonic bodies Platonic solids (or: ideal solids, regular polyhedra &#8212; &#8220;polyhedra&#8220;) are convex solids with the greatest possible regularity, named after the Greek philosopher Plato (427&#8211;347 BC). (Here a body is called convex if with two each of its points and also all points on the connecting line belong to it). This <a href=\"https:\/\/erlebnisland-mathematik.de\/en\/advanced-text-polyhedral-crown-platonic-solids\/\" class=\"more-link\">&#8230;<span class=\"screen-reader-text\">  Advanced Text Polyhedral Crown (Platonic Solids)<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"folder":[],"class_list":["post-3745","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/pages\/3745","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/comments?post=3745"}],"version-history":[{"count":17,"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/pages\/3745\/revisions"}],"predecessor-version":[{"id":4711,"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/pages\/3745\/revisions\/4711"}],"wp:attachment":[{"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/media?parent=3745"}],"wp:term":[{"taxonomy":"folder","embeddable":true,"href":"https:\/\/erlebnisland-mathematik.de\/en\/wp-json\/wp\/v2\/folder?post=3745"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}