{"id":165,"date":"2017-08-29T16:52:40","date_gmt":"2017-08-29T23:52:40","guid":{"rendered":"http:\/\/theothermath.com\/?p=165"},"modified":"2019-03-21T17:44:51","modified_gmt":"2019-03-22T00:44:51","slug":"what-is-a-trapezoid","status":"publish","type":"post","link":"https:\/\/theothermath.com\/index.php\/2017\/08\/29\/what-is-a-trapezoid\/","title":{"rendered":"What is a Trapezoid?"},"content":{"rendered":"<p><span style=\"font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">A famous bard once said, \u201cA trapezoid by any other name would still be a trapezium\u201d.<\/span><\/p>\n<p class=\"c2\"><span class=\"c1\">Okay&#8230;totally not true. But it brings to mind the question I am often asked, \u201cWhat is the definition of a trapezoid?\u201d In fact, I was asked this question today. So here is my answer\u2026<\/span><\/p>\n<hr \/>\n<p class=\"c0\"><span class=\"c1\">For mathematics, being a subject that is supposedly the \u201cuniversal language\u201d, this question opens a huge can of worms and has a surprisingly involved answer.<\/span><\/p>\n<p class=\"c0\"><span class=\"c1\">There are three \u2013 yes three \u2013 different ways one can define a trapezoid. Let\u2019s get started.<\/span><\/p>\n<p class=\"c0\"><span class=\"c1\">If a person walks up to you and says, \u201cLet\u2019s discuss trapezoids\u201d, the first things you should do is listen his accent. Is it American? Is it Canadian? Or some other English-speaking accent? This matters.<\/span><\/p>\n<p class=\"c0\">For the words <span class=\"c11\">trapezoid<\/span> and <span class=\"c11\">trapezium<\/span>, America and Canada defines them one way, but in other English speaking countries these same two words have their meanings switched.<\/p>\n<table class=\"c7\">\n<tbody>\n<tr class=\"c15\">\n<td class=\"c14\" colspan=\"2\" rowspan=\"1\">\n<p class=\"c12\"><span class=\"c22\">In America and Canada&#8230;<\/span><\/p>\n<\/td>\n<\/tr>\n<tr class=\"c18\">\n<td class=\"c4\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c6\"><span class=\"c1\">trapezium<\/span><\/p>\n<\/td>\n<td class=\"c4\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c6\"><span class=\"c1\">trapezoid<\/span><\/p>\n<\/td>\n<\/tr>\n<tr class=\"c18\">\n<td class=\"c4\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c10\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 174.50px; height: 108.88px;\"><img style=\"width: 174.50px; height: 108.88px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/swjph_mbcqHUeM8sEZnKylg\/image?rev=3&amp;h=108&amp;w=174&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<\/td>\n<td class=\"c4\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c10\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 218.00px; height: 83.50px;\"><img style=\"width: 218.00px; height: 83.50px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/sodUjKNFxoIKChxPxbaH8lg\/image?rev=22&amp;h=83&amp;w=218&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<table class=\"c7\">\n<tbody>\n<tr class=\"c15\">\n<td class=\"c14\" colspan=\"2\" rowspan=\"1\">\n<p class=\"c12\"><span class=\"c22\">In other English speaking countries&#8230;<\/span><\/p>\n<\/td>\n<\/tr>\n<tr class=\"c18\">\n<td class=\"c4\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c6\"><span class=\"c1\">trapezium<\/span><\/p>\n<\/td>\n<td class=\"c4\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c6\"><span class=\"c1\">trapezoid<\/span><\/p>\n<\/td>\n<\/tr>\n<tr class=\"c18\">\n<td class=\"c4\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c10\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 218.00px; height: 83.50px;\"><img style=\"width: 218.00px; height: 83.50px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/sAkevvJyCMnHIyMw0cUOkIg\/image?rev=1&amp;h=83&amp;w=218&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<\/td>\n<td class=\"c4\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c10\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 174.50px; height: 108.88px;\"><img style=\"width: 174.50px; height: 108.88px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/sOZy9sVh4-wAY4dAm6jbwYg\/image?rev=1&amp;h=108&amp;w=174&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"c0\">\u00a0<span class=\"c1\">In America a trapezium is a quadrilateral that has no parallel sides. Sometimes this is called an irregular quadrilateral.<\/span><\/p>\n<p class=\"c0\">\u00a0So now that we have define a trapezoid to be the figure that is not a trapezium. There is still the matter of the two definitions of <span class=\"c11\">trapezoid<\/span><span class=\"c1\"> in America.<\/span><\/p>\n<p class=\"c0\">\u00a0<span class=\"c1\">Let\u2019s start with this figure\u2026<\/span><\/p>\n<p class=\"c10\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 218.00px; height: 83.50px;\"><img style=\"width: 218.00px; height: 83.50px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/sK7uA945T5XAa7he1ufmBFg\/image?rev=1&amp;h=83&amp;w=218&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<p class=\"c0\">\u00a0<span class=\"c1\">Most people would immediately recognize it as a trapezoid. There are two ways we can classify as trapezoid: the inclusive definition and the exclusive definition.<\/span><\/p>\n<ul>\n<li class=\"c0\">T(I): a figure with <span class=\"c11\">at least<\/span><span class=\"c1\"> one pair of parallel sides<\/span><\/li>\n<li class=\"c2\">T(E): a figure with <span class=\"c11\">exactly<\/span><span class=\"c1\"> one pair of parallel sides<\/span><\/li>\n<\/ul>\n<p class=\"c0\">\u00a0<span class=\"c1\">Both definitions are legitimate, but they each lead to other differences in classifications.<\/span><\/p>\n<p class=\"c0\">\u00a0<span class=\"c1\">For example, a parallelogram is just a parallelogram in T(E), but a parallelogram is also a trapezoid in T(I).<\/span><\/p>\n<p class=\"c2\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 330.00px; height: 106.00px;\"><img style=\"width: 330.00px; height: 106.00px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/sa-kfn6G57FQObILIm9XVng\/image?rev=72&amp;h=106&amp;w=330&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<p class=\"c2\"><span class=\"c1\">In T(I), even a square is considered a trapezoid!<\/span><\/p>\n<p class=\"c2\"><strong><span class=\"c1\">Why can\u2019t we all just get along?<\/span><\/strong><\/p>\n<p class=\"c2\"><span class=\"c1\">We don\u2019t need to argue over which definition is correct. They both are. So, this means when we speak about trapezoids, we must preface it with an agreement of which definition we are using&#8230;at least for that instance.<\/span><\/p>\n<p class=\"c0\">\u00a0<span class=\"c1\">T(E) seems to have its origins in the 1500\u2019s prior to the advent of calculus. When calculus came along, we began using trapezoids to estimate the area under curves.<\/span><\/p>\n<p class=\"c2\"><img loading=\"lazy\" class=\"alignnone \" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/d\/dd\/Trapezoidal_rule_illustration.png\/1200px-Trapezoidal_rule_illustration.png\" width=\"409\" height=\"311\" \/><\/p>\n<p class=\"c2\"><img loading=\"lazy\" class=\"alignnone size-full\" src=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/7\/7e\/Trapezium2.gif\" width=\"500\" height=\"300\" \/><\/p>\n<p class=\"c0\">\u00a0<span class=\"c1\">As the animation shows, some of the trapezoid slices begin to look suspiciously like rectangles. Aha!!! This is when T(I) got invented.<\/span><\/p>\n<p class=\"c0\"><em><strong>\u00a0<span class=\"c1\">Common Core Standards<\/span><\/strong><\/em><\/p>\n<p class=\"c2\">In <span class=\"c13\"><a class=\"c3\" href=\"https:\/\/www.google.com\/url?q=http:\/\/www.corestandards.org\/Math\/Content\/5\/G\/&amp;sa=D&amp;ust=1504052915553000&amp;usg=AFQjCNFME-lFq-BXbUk7D7ZSh4Z2SID9Iw\">5th grade the standards<\/a><\/span><sup><a id=\"ftnt_ref1\" href=\"#ftnt1\">[1]<\/a><\/sup><span class=\"c1\"> are non-committal on the trapezoid issue. <\/span><\/p>\n<p class=\"c2\"><span style=\"overflow: hidden; display: inline-block; margin: -0.00px 0.00px; border: 1.33px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 484.50px; height: 163.10px;\"><img style=\"width: 484.50px; height: 163.10px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/lh5.googleusercontent.com\/TsT7ZGUCpxacuDoK7xDxn_H4ZDH7hoH4Ws_if6BYiXThd_2EcMH4ZEpHE_KS5OsJWkIMQo8XEiMdZBGEegk62inIDXvG1Ek1JXs8boQrOuRlC2ZbQNFFWQb35c-zpkKFbVBcbKWP\" alt=\"6ERL0Y\" \/><\/span><\/p>\n<p class=\"c2\">The <span class=\"c13\"><a class=\"c3\" href=\"https:\/\/www.google.com\/url?q=http:\/\/www.corestandards.org\/Math\/Content\/3\/G\/&amp;sa=D&amp;ust=1504052915554000&amp;usg=AFQjCNHVBEian-y-z81BsswP7GpcZroqBg\">3rd grade standards<\/a><\/span><sup><a id=\"ftnt_ref2\" href=\"#ftnt2\">[2]<\/a><\/sup><span class=\"c1\"> also sidestep the issue.<\/span><\/p>\n<p class=\"c2\"><span style=\"overflow: hidden; display: inline-block; margin: -0.00px -0.00px; border: 1.33px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 514.50px; height: 152.39px;\"><img style=\"width: 514.50px; height: 152.39px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/lh4.googleusercontent.com\/dLCVW1vMaGsbnHIqgve6Tb059dbw6ERWpbEBnVHazYE3bD5wLgBCz9lbecPbLhgZj4Pq6w-yCNxWbH8YJLZTtuXAKN_N_JjKlxrC-2I1_22YMgtnUoP5c4YEUAibZFfh4io4BmAk\" alt=\"m0KsEk\" \/><\/span><\/p>\n<p class=\"c2\">But the <span class=\"c13\"><a class=\"c3\" href=\"https:\/\/www.google.com\/url?q=http:\/\/math.arizona.edu\/~ime\/progressions\/&amp;sa=D&amp;ust=1504052915555000&amp;usg=AFQjCNF62pRonbqF9WIU70e6-mybG61NjA\">Progressions Documents for the Common Core Math Standards<\/a><\/span><sup><a id=\"ftnt_ref3\" href=\"#ftnt3\">[3]<\/a><\/sup><span class=\"c1\"> make it clear that mathematicians prefer we use T(I). <\/span><\/p>\n<p class=\"c2\"><span style=\"overflow: hidden; display: inline-block; margin: -0.00px 0.00px; border: 1.33px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 344.48px; height: 208.50px;\"><img style=\"width: 344.48px; height: 208.50px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/lh3.googleusercontent.com\/PKNGRPIR7FANcJn4RsG_Urqnzwsf58WbRtUPKJm3Pgc2orbKycJVBdmBiKfR_tsEgRRXubuNQrwe-ux0p5PcaS_wtY-88TkICPh-Lw0nzikeMhHVNsYFIcPLZSmBckgSNoAgyobq\" alt=\"95qC8I\" \/><\/span><\/p>\n<p class=\"c0\">\u00a0Since a key component of the Common Core Standards is that students will be <span class=\"c13\"><a class=\"c3\" href=\"https:\/\/www.google.com\/url?q=http:\/\/www.corestandards.org\/about-the-standards\/&amp;sa=D&amp;ust=1504052915556000&amp;usg=AFQjCNGGJ7mKf63iqnWm6VoIuxbwhxwbJA\">college and career ready<\/a><\/span><sup><a id=\"ftnt_ref4\" href=\"#ftnt4\">[4]<\/a><\/sup><span class=\"c1\">, it seems the best trapezoid definition to use is the one that leads to calculus&#8230;T(I).<\/span><\/p>\n<p class=\"c0\">\u00a0<span class=\"c1\">These are all trapezoids\u2026<\/span><\/p>\n<table class=\"c7\">\n<tbody>\n<tr class=\"c18\">\n<td class=\"c20\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c10\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 176.00px; height: 67.82px;\"><img style=\"width: 176.00px; height: 67.82px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/sjajTBPs-f2nwCBgMi-8pwg\/image?rev=1&amp;h=67&amp;w=176&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<\/td>\n<td class=\"c17\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c10\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 229.00px; height: 73.41px;\"><img style=\"width: 229.00px; height: 73.41px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/sDqTmAybIKb0scIppJ4dRRQ\/image?rev=1&amp;h=73&amp;w=229&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<\/td>\n<td class=\"c21\" colspan=\"1\" rowspan=\"1\">\n<p class=\"c10\"><span style=\"overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 78.00px; height: 78.00px;\"><img style=\"width: 78.00px; height: 78.00px; margin-left: 0.00px; margin-top: 0.00px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);\" title=\"\" src=\"https:\/\/docs.google.com\/drawings\/d\/sYmdXj4JxyRpXzFYyxV0HvA\/image?rev=3&amp;h=78&amp;w=78&amp;ac=1\" alt=\"\" \/><\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"c0\">\u00a0<span class=\"c1\">A trapezoid is a quadrilateral with at least one pair of parallel sides.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A famous bard once said, \u201cA trapezoid by any other name would still be a trapezium\u201d. Okay&#8230;totally not true. But it brings to mind the question I am often asked, \u201cWhat is the definition of a trapezoid?\u201d In fact, I was asked this question today. So here is my answer\u2026 For mathematics, being a subject [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[4],"tags":[],"_links":{"self":[{"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/posts\/165"}],"collection":[{"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/comments?post=165"}],"version-history":[{"count":2,"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/posts\/165\/revisions"}],"predecessor-version":[{"id":167,"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/posts\/165\/revisions\/167"}],"wp:attachment":[{"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/media?parent=165"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/categories?post=165"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/theothermath.com\/index.php\/wp-json\/wp\/v2\/tags?post=165"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}