{"id":4379,"date":"2013-06-29T05:47:42","date_gmt":"2013-06-29T05:47:42","guid":{"rendered":"http:\/\/www.mometrix.com\/academy\/?page_id=4379"},"modified":"2026-03-28T11:17:26","modified_gmt":"2026-03-28T16:17:26","slug":"area-and-perimeter-of-a-triangle","status":"publish","type":"page","link":"https:\/\/www.mometrix.com\/academy\/area-and-perimeter-of-a-triangle\/","title":{"rendered":"Area and Perimeter of a Triangle"},"content":{"rendered":"\n\t\t\t<div id=\"mmDeferVideoEncompass_rWbtDB-PViU\" style=\"position: relative;\">\n\t\t\t<picture>\n\t\t\t\t<source srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2023\/01\/circle-play-duotone.webp\" type=\"image\/webp\">\n\t\t\t\t<source srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2023\/01\/circle-play-duotone.png\" type=\"image\/jpeg\"> \n\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" loading=\"eager\" id=\"videoThumbnailImage_rWbtDB-PViU\" data-source-videoID=\"rWbtDB-PViU\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2023\/01\/circle-play-duotone.png\" alt=\"Area and Perimeter of a Triangle Video\" height=\"464\" width=\"825\" class=\"size-full\" data-matomo-title = \"Area and Perimeter of a Triangle\">\n\t\t\t<\/picture>\n\t\t\t<\/div>\n\t\t\t<style>img#videoThumbnailImage_rWbtDB-PViU:hover {cursor:pointer;} img#videoThumbnailImage_rWbtDB-PViU {background-size:contain;background-image:url(\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2023\/02\/1234-area-and-perimeter-of-a-triangle-1.webp\");}<\/style>\n\t\t\t<script defer>\n\t\t\t  jQuery(\"img#videoThumbnailImage_rWbtDB-PViU\").click(function() {\n\t\t\t\tlet videoId = jQuery(this).attr(\"data-source-videoID\");\n\t\t\t\tlet helpTag = '<div id=\"mmDeferVideoYTMessage_rWbtDB-PViU\" style=\"display: none;position: absolute;top: -24px;width: 100%;text-align: center;\"><span style=\"font-style: italic;font-size: small;border-top: 1px solid #fc0;\">Having trouble? <a href=\"https:\/\/www.youtube.com\/watch?v='+videoId+'\" target=\"_blank\">Click here to watch on YouTube.<\/a><\/span><\/div>';\n\t\t\t\tlet tag = document.createElement(\"iframe\");\n\t\t\t\ttag.id = \"yt\" + videoId;\n\t\t\t\ttag.src = \"https:\/\/www.youtube-nocookie.com\/embed\/\" + videoId + \"?autoplay=1&controls=1&wmode=opaque&rel=0&egm=0&iv_load_policy=3&hd=0&enablejsapi=1\";\n\t\t\t\ttag.frameborder = 0;\n\t\t\t\ttag.allow = \"autoplay; fullscreen\";\n\t\t\t\ttag.width = this.width;\n\t\t\t\ttag.height = this.height;\n\t\t\t\ttag.setAttribute(\"data-matomo-title\",\"Area and Perimeter of a Triangle\");\n\t\t\t\tjQuery(\"div#mmDeferVideoEncompass_rWbtDB-PViU\").html(tag);\n\t\t\t\tjQuery(\"div#mmDeferVideoEncompass_rWbtDB-PViU\").prepend(helpTag);\n\t\t\t\tsetTimeout(function(){jQuery(\"div#mmDeferVideoYTMessage_rWbtDB-PViU\").css(\"display\", \"block\");}, 2000);\n\t\t\t  });\n\t\t\t  \n\t\t\t<\/script>\n\t\t\n<p><script>\nfunction PAu_Function() {\n  var x = document.getElementById(\"PAu\");\n  if (x.style.display === \"none\") {\n    x.style.display = \"block\";\n  } else {\n    x.style.display = \"none\";\n  }\n}\n<\/script><\/p>\n<div class=\"moc-toc hide-on-desktop hide-on-tablet\">\n<div><button onclick=\"PAu_Function()\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2024\/12\/toc2.svg\" width=\"16\" height=\"16\" alt=\"show or hide table of contents\"><\/button><\/p>\n<p>On this page<\/p>\n<\/div>\n<nav id=\"PAu\" style=\"display:none;\">\n<ul>\n<li class=\"toc-h2\"><a href=\"#How_to_find_the_Perimeter_of_a_Triangle\" class=\"smooth-scroll\">How to find the Perimeter of a Triangle<\/a><\/li>\n<li class=\"toc-h2\"><a href=\"#How_to_find_the_Area_of_a_Triangle\" class=\"smooth-scroll\">How to find the Area of a Triangle<\/a><\/li>\n<li class=\"toc-h2\"><a href=\"#Frequently_Asked_Questions\" class=\"smooth-scroll\">Frequently Asked Questions<\/a><\/li>\n<li class=\"toc-h2\"><a href=\"#Area_and_Perimeter_of_a_Triangle_Practice_Questions\" class=\"smooth-scroll\">Area and Perimeter of a Triangle Practice Questions<\/a><\/li>\n<\/ul>\n<\/nav>\n<\/div>\n<div class=\"accordion\"><input id=\"transcript\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"transcript\">Transcript<\/label><input id=\"FAQs\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"FAQs\">FAQs<\/label><input id=\"PQs\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQs\">Practice<\/label>\n<div class=\"spoiler\" id=\"transcript-spoiler\">\n<p>Hi, and welcome to this video on the perimeter and area of a triangle!<\/p>\n<p>To get started, let\u2019s quickly review what <a class=\"ylist\" href=\"https:\/\/www.mometrix.com\/academy\/area-and-perimeter\/\">perimeter and area<\/a> measure. Imagine we have a triangular-shaped yard.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-yardd.png\" alt=\"\" width=\"262.6\" height=\"234\" class=\"aligncenter size-full wp-image-86443\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-yardd.png 394w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-yardd-300x267.png 300w\" sizes=\"(max-width: 394px) 100vw, 394px\" \/><\/p>\n<p>If we wanted to build a fence around our yard, we\u2019d need to know the distance around the yard. This is the <strong>perimeter<\/strong>. If we wanted to buy sod for our yard, we\u2019d need to know the <strong>area<\/strong> of the yard so that we can buy the correct amount. <\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-a-and-p.png\" alt=\"\" width=\"663.3\" height=\"272\" class=\"aligncenter size-full wp-image-86446\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-a-and-p.png 995w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-a-and-p-300x123.png 300w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-a-and-p-768x315.png 768w\" sizes=\"(max-width: 995px) 100vw, 995px\" \/><\/p>\n<p>And while it might be a bit unusual to have a yard that is the shape of a triangle, you might have a <strong>part<\/strong> of a yard that you want to fence or sod shaped like a triangle.<\/p>\n<h2><span id=\"How_to_find_the_Perimeter_of_a_Triangle\" class=\"m-toc-anchor\"><\/span>How to find the Perimeter of a Triangle<\/h2>\n<p>Okay, now that we know what perimeter and area are, let\u2019s figure out how to find the <strong>perimeter<\/strong>. We don\u2019t need a fancy formula or anything. All we need to do is add the length of the sides together. So if we know all the sides of our yard we can easily find the perimeter: <\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-yard-numbers.png\" alt=\"\" width=\"294.6\" height=\"274\" class=\"aligncenter size-full wp-image-86449\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-yard-numbers.png 442w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-yard-numbers-300x279.png 300w\" sizes=\"(max-width: 442px) 100vw, 442px\" \/><\/p>\n<p>\\(20m+20m+12m=52m\\) of fence. Not much to that one. Notice that the answer is given in meters. That\u2019s because perimeter is a distance. Walking around the yard would mean walking 52 meters.<\/p>\n<p>That\u2019s all there is to it, no matter what type of triangle you have. Just add up the length of the sides and you have your perimeter.<\/p>\n<h2><span id=\"How_to_find_the_Area_of_a_Triangle\" class=\"m-toc-anchor\"><\/span>How to find the Area of a Triangle<\/h2>\n<p>Now let\u2019s deal with area. There\u2019s an actual formula for finding the area of a triangle, which is \\(A= \\frac{1}{2}bh\\)<\/p>\n<p>Let\u2019s quickly explain where that \\(\\frac{1}{2}\\) came from. The formula for the area of a parallelogram is \\(A=bh\\). If we compare the two shapes, we can see that a parallelogram can be made by two equal-sized triangles:<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/trianglezoids-cropped.png\" alt=\"\" width=\"436.8\" height=\"130.6\" class=\"aligncenter size-full wp-image-86467\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/trianglezoids-cropped.png 983w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/trianglezoids-cropped-300x90.png 300w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/trianglezoids-cropped-768x230.png 768w\" sizes=\"(max-width: 983px) 100vw, 983px\" \/><\/p>\n<p>So we can say a triangle is half a parallelogram, which is where the one half comes from in the formula.<\/p>\n<p>For triangles, the formula for area does work a bit differently depending on the type of triangle. Let\u2019s start with right triangles.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/right-triangle.png\" alt=\"\" width=\"250\" height=\"249\" class=\"aligncenter size-full wp-image-86473\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/right-triangle.png 250w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/right-triangle-150x150.png 150w\" sizes=\"auto, (max-width: 250px) 100vw, 250px\" \/><\/p>\n<p>We have our formula, but the question we need to answer is which side is \\(b\\) and which side is \\(h\\)? <\/p>\n<p>For a right triangle like this one, \\(b\\) and \\(h\\) are the two sides adjacent, or next to, the right angle. It doesn\u2019t matter which is which, so let\u2019s say that \\(b=6\\) cm and \\(h=8\\) cm.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/right-triangle-withj-numbers.png\" alt=\"\" width=\"319\" height=\"274\" class=\"aligncenter size-full wp-image-86482\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/right-triangle-withj-numbers.png 319w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/right-triangle-withj-numbers-300x258.png 300w\" sizes=\"auto, (max-width: 319px) 100vw, 319px\" \/><\/p>\n<p>Now we can plug them into our formula: <\/p>\n<div class=\"examplesentence\">\\(A=\\frac{1}{2}(6 \\text{ cm})(8 \\text{ cm})\\)<\/div>\n<p>\n&nbsp;<br \/>\nIt\u2019s always a good idea to substitute with parentheses to help keep things organized. We\u2019ve even left the units in so that we can see what will happen with them. At this point, we only have multiplication left to do, so according to the <a class=\"ylist\" href=\"https:\/\/www.mometrix.com\/academy\/associative-property\/\">commutative property of multiplication<\/a>, we can rearrange before multiplying:<\/p>\n<div class=\"examplesentence\">\\(A=\\frac{1}{2}(6)(8)(\\text{cm})(\\text{cm})\\)<\/div>\n<p>\n&nbsp;<br \/>\nNow let\u2019s solve this:<\/p>\n<div class=\"examplesentence\">\\(\\frac{1}{2} \\times 6=3\\)<br \/>\n\\(3\\times 8=24\\)<br \/>\n\\(\\text{cm} \\times \\text{cm}= \\text{cm}^2\\)<\/div>\n<p>\n&nbsp;<br \/>\nSo, we end up with our area as 24 cm\\(^2\\).<\/p>\n<p>For area problems, the answer will always be in square units. That\u2019s because we\u2019re trying to determine how many square centimeters will fit in our triangle. We can see that clearly by looking at an isosceles right triangle that has legs measuring 5 units on some graph paper:<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/grid-triangle-no-numbers.png\" alt=\"\" width=\"377.3\" height=\"340\" class=\"aligncenter size-full wp-image-86491\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/grid-triangle-no-numbers.png 566w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/grid-triangle-no-numbers-300x270.png 300w\" sizes=\"(max-width: 566px) 100vw, 566px\" \/><\/p>\n<p>How many squares are inside the triangle? We can count them. First, we\u2019ll count the whole squares that fit inside, then we\u2019ll add the half squares:<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/grid-triangle-with-numbers.png\" alt=\"\" width=\"377.3\" height=\"340\" class=\"aligncenter size-full wp-image-86494\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/grid-triangle-with-numbers.png 566w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/grid-triangle-with-numbers-300x270.png 300w\" sizes=\"(max-width: 566px) 100vw, 566px\" \/><\/p>\n<p>There are 10 full squares plus 5 half squares for a total of 12\\(\\frac{1}{2}\\) squares. <\/p>\n<p>If we use our formula we\u2019ll find the same thing:<\/p>\n<div class=\"examplesentence\">\\(A=\\frac{1}{2}(5)(5)\\)<br \/>\n\\(A=\\frac{1}{2}(25)\\)<br \/>\n\\(A=12.5\\)<\/div>\n<p>\n&nbsp;<br \/>\nNow we\u2019ve seen the formula work and gained a better understanding of why the units are squared. All we have left to do is find the area of acute and obtuse triangles. <\/p>\n<p>Let\u2019s start with an <strong>acute<\/strong> triangle:<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/acute-triangle-measured-cropped.png\" alt=\"\" width=\"299.3\" height=\"293.3\" class=\"aligncenter size-full wp-image-86500\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/acute-triangle-measured-cropped.png 449w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/acute-triangle-measured-cropped-300x294.png 300w\" sizes=\"(max-width: 449px) 100vw, 449px\" \/><\/p>\n<p>Note that the height is always perpendicular to the base. From here we can find the area:<\/p>\n<div class=\"examplesentence\">\\(A=\\frac{1}{2}(12)(8)\\)<br \/>\n\\(A=\\frac{1}{2}(96)\\)<br \/>\n\\(A=48\\text{ cm}^2\\)<\/div>\n<p>\n&nbsp;<br \/>\nThe same thing applies to <strong>obtuse<\/strong> triangles, except the height or altitude will often appear outside of the triangle, like this: <\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-obtuse-labeled-cropped.png\" alt=\"\" width=\"510\" height=\"287.3\" class=\"aligncenter size-full wp-image-86503\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-obtuse-labeled-cropped.png 765w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/triangle-obtuse-labeled-cropped-300x169.png 300w\" sizes=\"(max-width: 765px) 100vw, 765px\" \/><\/p>\n<p>We can see that the height of the triangle is 6 cm, and the side it is perpendicular to is the base, which measures 9 cm. We don\u2019t need the other two numbers at all. Let\u2019s plug in the base and height: <\/p>\n<div class=\"examplesentence\">\\(A=\\frac{1}{2}(9)(6)\\)<br \/>\n\\(A=\\frac{1}{2}(54)\\)<br \/>\n\\(A=27 \\text{ cm}^2\\)<\/div>\n<p>\n&nbsp;<br \/>\nThat\u2019s all there is to it! Here is one more for you to solve on your own. Try pausing this video and then finding the perimeter and area of this triangle.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/last-triangle-albeled.png\" alt=\"\" width=\"500\" height=\"237.3\" class=\"aligncenter size-full wp-image-86509\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/last-triangle-albeled.png 750w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/07\/last-triangle-albeled-300x142.png 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" \/><\/p>\n<p>Think you got it? The perimeter is 34 m and the area is 49 m\\(^2\\).<\/p>\n<p>Thanks for watching, and happy studying!<\/p>\n<\/div>\n<div class=\"spoiler\" id=\"FAQs-spoiler\">\n<h2 style=\"text-align:center\"><span id=\"Frequently_Asked_Questions\" class=\"m-toc-anchor\"><\/span>Frequently Asked Questions<\/h2>\n<div class=\"faq-list\">\n<div class=\"qa_wrap\">\n<div class=\"q_item text_bold\">\n<h4 class=\"letter\">Q<\/h4>\n<p style=\"line-height: unset;\">How do you find the area of a triangle?<\/p>\n<\/p><\/div>\n<div class=\"a_item\">\n<h4 class=\"letter text_bold\">A<\/h4>\n<p>Find the area of a triangle by multiplying its base times its height and dividing by two.<\/p>\n<p style=\"text-align: center\">\\(A=\\frac{1}{2} bh\\)<\/p>\n<div class=\"lightbulb-example-2\" style=\"min-width: 70%\"><span class=\"lightbulb-icon\">\ud83d\udca1<\/span><span class=\"faq-example-question\">Example: What is the area of this triangle:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2025\/10\/Area-of-a-triangle-example.svg\" alt=\"Triangle with a base of 6 inches, two equal sides of 7 inches each, and a dashed line indicating the height from the top vertex to the base.\" width=\"226\" height=\"237\" class=\"aligncenter size-full wp-image-273931\"  role=\"img\" \/><\/p>\n<hr style=\"padding: 0; margin-top: -0.2em; margin-bottom: 1.2em\">\n<p style=\"text-align: center; margin-bottom: 0em\">\\(A=\\frac{1}{2} bh=\\frac{1}{2} (6)(7)=21\\text{ in}^2\\)<\/p>\n<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div class=\"qa_wrap\">\n<div class=\"q_item text_bold\">\n<h4 class=\"letter\">Q<\/h4>\n<p style=\"line-height: unset;\">How do you find the perimeter of a triangle?<\/p>\n<\/p><\/div>\n<div class=\"a_item\">\n<h4 class=\"letter text_bold\">A<\/h4>\n<p>Find the perimeter of a triangle by adding the lengths of all three sides together.<\/p>\n<div class=\"lightbulb-example-2\" style=\"min-width: 70%\"><span class=\"lightbulb-icon\">\ud83d\udca1<\/span><span class=\"faq-example-question\">Example: What is the perimeter of this triangle?<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2025\/10\/Perimeter-of-a-triangle-example.svg\" alt=\"A triangle with side lengths labeled 7 cm, 8 cm, and 16 cm.\" width=\"349\" height=\"152\" class=\"aligncenter size-full wp-image-273934\"  role=\"img\" \/><\/p>\n<hr style=\"padding: 0; margin-top: -0.2em; margin-bottom: 1.2em\">\n<p style=\"text-align: center; margin-bottom: 0em\">\\(P = 7 + 8 + 16 = 31 \\mathrm{\\:cm}\\)<\/p>\n<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div class=\"qa_wrap\">\n<div class=\"q_item text_bold\">\n<h4 class=\"letter\">Q<\/h4>\n<p style=\"line-height: unset;\">How do you find the area of a right triangle?<\/p>\n<\/p><\/div>\n<div class=\"a_item\">\n<h4 class=\"letter text_bold\">A<\/h4>\n<p>Find the area of a right triangle by multiplying its base times its height and dividing by 2.<\/p>\n<p style=\"text-align: center\">\\(A=\\frac{1}{2} bh\\)<\/p>\n<div class=\"lightbulb-example-2\" style=\"min-width: 70%\"><span class=\"lightbulb-icon\">\ud83d\udca1<\/span><span class=\"faq-example-question\">Example: What is the area of this right triangle?<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2025\/10\/Area-of-a-right-triangle-example.svg\" alt=\"A right triangle with a height of 3 feet and a base of 4 feet.\" width=\"268\" height=\"183\" class=\"aligncenter size-full wp-image-273937\"  role=\"img\" \/><\/p>\n<hr style=\"padding: 0; margin-top: -0.2em; margin-bottom: 1.2em\">\n<p style=\"text-align: center; margin-bottom: 0em\">\\(A=\\frac{1}{2} bh=\\frac{1}{2} (3)(4)=6\\text{ ft}^2\\)<\/p>\n<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div class=\"qa_wrap\">\n<div class=\"q_item text_bold\">\n<h4 class=\"letter\">Q<\/h4>\n<p style=\"line-height: unset;\">How do you find the perimeter of a right triangle?<\/p>\n<\/p><\/div>\n<div class=\"a_item\">\n<h4 class=\"letter text_bold\">A<\/h4>\n<p>Find the perimeter of a right triangle by adding the measures of all three sides together.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/div>\n<\/div>\n<div class=\"spoiler\" id=\"PQs-spoiler\">\n<h2 style=\"text-align:center\"><span id=\"Area_and_Perimeter_of_a_Triangle_Practice_Questions\" class=\"m-toc-anchor\"><\/span>Area and Perimeter of a Triangle Practice Questions<\/h2>\n\n\t\t\t\t<div class=\"PQ\">\n\t\t\t\t\t<strong>Question #1:<\/strong>\n\t\t\t\t\t<div style=\"margin-left:10px;\"><p>&nbsp;<br \/>\nWhat is the perimeter of this triangle?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2025\/10\/Perimeter-of-a-triangle-example-2.svg\" alt=\"A triangle with sides labeled 3 cm, 9 cm, and 11 cm.\" width=\"362\" height=\"139\" class=\"aligncenter size-full wp-image-273943\"  role=\"img\" \/><\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ\"  id=\"PQ-1-1\">25 cm<\/div><div class=\"PQ\"  id=\"PQ-1-2\">14 cm<\/div><div class=\"PQ correct_answer\"  id=\"PQ-1-3\">23 cm<\/div><div class=\"PQ\"  id=\"PQ-1-4\">17 cm<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<input id=\"PQ-1\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-1\" style=\"width: 150px;\">Show Answer<\/label>\n\t\t\t\t\t<div class=\"answer\" id=\"PQ-1-spoiler\">\n\t\t\t\t\t\t<strong>Answer:<\/strong><div style=\"margin-left:10px;\"><p>To find the perimeter of a polygon, add the lengths of all the sides together.<\/p>\n<p style=\"text-align:center;\">\\(P=3+11+9=23\\text{ cm}\\)<\/p>\n<\/div>\n\t\t\t\t\t\t<input id=\"PQ-1-hide\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-1-hide\" style=\"width: 150px;\">Hide Answer<\/label>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"PQ\">\n\t\t\t\t\t<strong>Question #2:<\/strong>\n\t\t\t\t\t<div style=\"margin-left:10px;\"><p>&nbsp;<br \/>\nWhat is the area of this triangle?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2025\/10\/Area-of-a-right-triangle-example-2.svg\" alt=\"Right triangle with a vertical leg labeled 4 ft, a horizontal leg labeled 3 ft, and a right angle at the bottom left corner.\" width=\"231\" height=\"241\" class=\"aligncenter size-full wp-image-273946\"  role=\"img\" \/><\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ correct_answer\"  id=\"PQ-2-1\">6 ft<sup>2<\/sup><\/div><div class=\"PQ\"  id=\"PQ-2-2\">12 ft<sup>2<\/sup><\/div><div class=\"PQ\"  id=\"PQ-2-3\">3 ft<sup>2<\/sup><\/div><div class=\"PQ\"  id=\"PQ-2-4\">9 ft<sup>2<\/sup><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<input id=\"PQ-2\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-2\" style=\"width: 150px;\">Show Answer<\/label>\n\t\t\t\t\t<div class=\"answer\" id=\"PQ-2-spoiler\">\n\t\t\t\t\t\t<strong>Answer:<\/strong><div style=\"margin-left:10px;\"><p>To find the area of a triangle, use this formula:<\/p>\n<p style=\"text-align:center;\">\\(A=\\frac{1}{2}bh\\)<\/p>\n<p>The base (\\(b\\)) is 3 feet and the height (\\(h\\)) is 4 feet.<\/p>\n<p style=\"text-align:center;\">\\(A=\\frac{1}{2}(3)(4)=6\\text{ ft}^2\\)<\/p>\n<\/div>\n\t\t\t\t\t\t<input id=\"PQ-2-hide\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-2-hide\" style=\"width: 150px;\">Hide Answer<\/label>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"PQ\">\n\t\t\t\t\t<strong>Question #3:<\/strong>\n\t\t\t\t\t<div style=\"margin-left:10px;\"><p>&nbsp;<br \/>\nWhat is the formula for perimeter of any triangle?<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ\"  id=\"PQ-3-1\">\\(P=3s\\)<\/div><div class=\"PQ correct_answer\"  id=\"PQ-3-2\">\\(P=a+b+c\\)<\/div><div class=\"PQ\"  id=\"PQ-3-3\">\\(P=a+b+c+d\\)<\/div><div class=\"PQ\"  id=\"PQ-3-4\">\\(P=2a+b\\)<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<input id=\"PQ-3\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-3\" style=\"width: 150px;\">Show Answer<\/label>\n\t\t\t\t\t<div class=\"answer\" id=\"PQ-3-spoiler\">\n\t\t\t\t\t\t<strong>Answer:<\/strong><div style=\"margin-left:10px;\"><p>To find the perimeter of a polygon, add together the lengths of each side:<\/p>\n<p style=\"text-align: center\">\\(P=a+b+c\\)<\/p>\n<\/div>\n\t\t\t\t\t\t<input id=\"PQ-3-hide\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-3-hide\" style=\"width: 150px;\">Hide Answer<\/label>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"PQ\">\n\t\t\t\t\t<strong>Question #4:<\/strong>\n\t\t\t\t\t<div style=\"margin-left:10px;\"><p>&nbsp;<br \/>\nWhat is the area of this triangle?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2025\/10\/Area-of-a-triangle-example-3.svg\" alt=\"A triangle with side lengths 9 in, 13 in, and 18 in. The height from the 18 in base to the top vertex is 7 in.\" width=\"380\" height=\"167\" class=\"aligncenter size-full wp-image-273949\"  role=\"img\" \/><\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ\"  id=\"PQ-4-1\">81 in<sup>2<\/sup><\/div><div class=\"PQ correct_answer\"  id=\"PQ-4-2\">63 in<sup>2<\/sup><\/div><div class=\"PQ\"  id=\"PQ-4-3\">74 in<sup>2<\/sup><\/div><div class=\"PQ\"  id=\"PQ-4-4\">126 in<sup>2<\/sup><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<input id=\"PQ-4\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-4\" style=\"width: 150px;\">Show Answer<\/label>\n\t\t\t\t\t<div class=\"answer\" id=\"PQ-4-spoiler\">\n\t\t\t\t\t\t<strong>Answer:<\/strong><div style=\"margin-left:10px;\"><p>The formula for area of a triangle is:<\/p>\n<p style=\"text-align:center;\">\\(A=\\frac{1}{2}bh\\)<\/p>\n<p>The base is 18 inches and the height is 7 inches.<\/p>\n<p style=\"text-align:center;\">\\(A=\\frac{1}{2}(18)(7)=63\\text{ in}^2\\)<\/p>\n<\/div>\n\t\t\t\t\t\t<input id=\"PQ-4-hide\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-4-hide\" style=\"width: 150px;\">Hide Answer<\/label>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"PQ\">\n\t\t\t\t\t<strong>Question #5:<\/strong>\n\t\t\t\t\t<div style=\"margin-left:10px;\"><p>&nbsp;<br \/>\nWhat is the perimeter of this isosceles triangle?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2025\/10\/Perimeter-of-an-isosceles-triangle-example.svg\" alt=\"A triangle with a base of 8 cm and two equal sides each measuring 13 cm.\" width=\"234\" height=\"250\" class=\"aligncenter size-full wp-image-273952\"  role=\"img\" \/><\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ\"  id=\"PQ-5-1\">32 cm<\/div><div class=\"PQ\"  id=\"PQ-5-2\">29 cm<\/div><div class=\"PQ\"  id=\"PQ-5-3\">21 cm<\/div><div class=\"PQ correct_answer\"  id=\"PQ-5-4\">34 cm<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<input id=\"PQ-5\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-5\" style=\"width: 150px;\">Show Answer<\/label>\n\t\t\t\t\t<div class=\"answer\" id=\"PQ-5-spoiler\">\n\t\t\t\t\t\t<strong>Answer:<\/strong><div style=\"margin-left:10px;\"><p>To find the perimeter of a polygon, add the lengths of all the sides together. Since this is an isosceles triangle, two of the sides measure 13 cm.<\/p>\n<p style=\"text-align:center;\">\\(P=13+13+8=34\\text{ cm}\\)<\/p>\n<\/div>\n\t\t\t\t\t\t<input id=\"PQ-5-hide\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQ-5-hide\" style=\"width: 150px;\">Hide Answer<\/label>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div><\/div>\n<\/div>\n\n<div class=\"home-buttons\">\n<p><a href=\"https:\/\/www.mometrix.com\/academy\/geometry\/\">Return to Geometry Videos<\/a><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Return to Geometry Videos<\/p>\n","protected":false},"author":1,"featured_media":100333,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":{"0":"post-4379","1":"page","2":"type-page","3":"status-publish","4":"has-post-thumbnail","6":"page_category-area-and-perimeter-videos","7":"page_category-finding-areas-in-geometry","8":"page_category-math-advertising-group","9":"page_category-triangle-videos","10":"page_type-video","11":"content_type-practice-questions","12":"subject_matter-math"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/pages\/4379","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/comments?post=4379"}],"version-history":[{"count":5,"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/pages\/4379\/revisions"}],"predecessor-version":[{"id":280898,"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/pages\/4379\/revisions\/280898"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/media\/100333"}],"wp:attachment":[{"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/media?parent=4379"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}