{"id":686,"date":"2013-05-28T14:32:46","date_gmt":"2013-05-28T14:32:46","guid":{"rendered":"http:\/\/www.mometrix.com\/academy\/?page_id=686"},"modified":"2026-03-28T11:12:02","modified_gmt":"2026-03-28T16:12:02","slug":"parallel-and-perpendicular-lines","status":"publish","type":"page","link":"https:\/\/www.mometrix.com\/academy\/parallel-and-perpendicular-lines\/","title":{"rendered":"Parallel and Perpendicular Lines"},"content":{"rendered":"\n\t\t\t<div id=\"mmDeferVideoEncompass_aVkAfHP3IRk\" 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_aVkAfHP3IRk\" data-source-videoID=\"aVkAfHP3IRk\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2023\/01\/circle-play-duotone.png\" alt=\"Parallel and Perpendicular Lines Video\" height=\"464\" width=\"825\" class=\"size-full\" data-matomo-title = \"Parallel and Perpendicular Lines\">\n\t\t\t<\/picture>\n\t\t\t<\/div>\n\t\t\t<style>img#videoThumbnailImage_aVkAfHP3IRk:hover {cursor:pointer;} img#videoThumbnailImage_aVkAfHP3IRk {background-size:contain;background-image:url(\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2023\/02\/69-parallel-and-perpendicular-lines-1.webp\");}<\/style>\n\t\t\t<script defer>\n\t\t\t  jQuery(\"img#videoThumbnailImage_aVkAfHP3IRk\").click(function() {\n\t\t\t\tlet videoId = jQuery(this).attr(\"data-source-videoID\");\n\t\t\t\tlet helpTag = '<div id=\"mmDeferVideoYTMessage_aVkAfHP3IRk\" 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\",\"Parallel and Perpendicular Lines\");\n\t\t\t\tjQuery(\"div#mmDeferVideoEncompass_aVkAfHP3IRk\").html(tag);\n\t\t\t\tjQuery(\"div#mmDeferVideoEncompass_aVkAfHP3IRk\").prepend(helpTag);\n\t\t\t\tsetTimeout(function(){jQuery(\"div#mmDeferVideoYTMessage_aVkAfHP3IRk\").css(\"display\", \"block\");}, 2000);\n\t\t\t  });\n\t\t\t  \n\t\t\t<\/script>\n\t\t\n<p><script>\nfunction OjW_Function() {\n  var x = document.getElementById(\"OjW\");\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=\"OjW_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=\"OjW\" style=\"display:none;\">\n<ul>\n<li class=\"toc-h2\"><a href=\"#What_Are_Lines\" class=\"smooth-scroll\">What Are Lines?<\/a><\/li>\n<li class=\"toc-h2\"><a href=\"#Parallel_and_Perpendicular_Lines\" class=\"smooth-scroll\">Parallel and Perpendicular Lines<\/a><\/li>\n<li class=\"toc-h2\"><a href=\"#Identifying_Types_of_Lines\" class=\"smooth-scroll\">Identifying Types of Lines<\/a><\/li>\n<li class=\"toc-h2\"><a href=\"#Parallel_and_Perpendicular_Lines_Practice_Questions\" class=\"smooth-scroll\">Parallel and Perpendicular Lines 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=\"PQs\" type=\"checkbox\" class=\"spoiler_button\" \/><label for=\"PQs\">Practice<\/label>\n<div class=\"spoiler\" id=\"transcript-spoiler\">\n<p>Hey, guys! Welcome to this video on parallel and perpendicular lines.<\/p>\n<h2><span id=\"What_Are_Lines\" class=\"m-toc-anchor\"><\/span>What Are Lines?<\/h2>\n<p>\nLines are everywhere you look. <a class=\"ylist\" href=\"https:\/\/www.mometrix.com\/academy\/finding-the-slope-of-a-line\/\">Lines<\/a> are formed on ceilings in classrooms, bedrooms, or whatever room you\u2019re in. Lines are on the roads we drive on, lines are on the signs we read, the paper we write on; lines are everywhere.<\/p>\n<p>But understanding and being able to identify what type of lines they are is a very important tool in the world. Architects and engineers, people who design buildings, need to know the types of lines so that they can build buildings that are safe, strong, stable, and won\u2019t randomly fall down on all the people inside.<\/p>\n<h2><span id=\"Parallel_and_Perpendicular_Lines\" class=\"m-toc-anchor\"><\/span>Parallel and Perpendicular Lines<\/h2>\n<p>\nNow, let\u2019s take a look at two of the most important types of lines: parallel and perpendicular lines.<\/p>\n<ul style=\"list-style-type: none;\">\n<li style=\"margin-bottom: 12px;\"><strong>Parallel lines<\/strong> are lines that run alongside each other but never intersect or cross with each other. Train tracks form parallel lines. The white lines on both sides of the road form parallel lines.<\/li>\n<li><strong>Perpendicular lines<\/strong> are lines that do cross, and when they do cross they always form right angles. Right angles are angles with a 90-degree angle. Perpendicular lines are formed in ceiling corners, desk corners, or really any corner with a 90-degree angle, or right angle.<\/li>\n<\/ul>\n<p>Let\u2019s take a look at some examples.<\/p>\n<h3><span id=\"Example_1\" class=\"m-toc-anchor\"><\/span>Example #1<\/h3>\n<p>\nAre these lines parallel or perpendicular?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-1-194x300.png\" alt=\"\" width=\"194\" height=\"300\" class=\"aligncenter size-medium wp-image-82813\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-1-194x300.png 194w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-1.png 392w\" sizes=\"auto, (max-width: 194px) 100vw, 194px\" \/><\/p>\n<p>Perpendicular, because the lines intersect and form a 90-degree angle, or right angle.<\/p>\n<h3><span id=\"Example_2\" class=\"m-toc-anchor\"><\/span>Example #2<\/h3>\n<p>\nNow, what type of lines are these?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-again-157x300.png\" alt=\"\" width=\"157\" height=\"300\" class=\"aligncenter size-medium wp-image-82810\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-again-157x300.png 157w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-again.png 400w\" sizes=\"auto, (max-width: 157px) 100vw, 157px\" \/><\/p>\n<p>These lines are parallel. See how they run alongside each other, but never intersect?<\/p>\n<h3><span id=\"Example_3\" class=\"m-toc-anchor\"><\/span>Example #3<\/h3>\n<p>\nLet\u2019s try another. Are these lines parallel or perpendicular?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-more-300x283.png\" alt=\"\" width=\"300\" height=\"283\" class=\"aligncenter size-medium wp-image-82816\" srcset=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-more-300x283.png 300w, https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2021\/06\/lines-more.png 447w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p>Neither, because even though the lines cross, they do not form right angles. <\/p>\n<p>You guys are doing great! Sometimes, learning can be tough, but you just have to keep trying.<\/p>\n<h2><span id=\"Identifying_Types_of_Lines\" class=\"m-toc-anchor\"><\/span>Identifying Types of Lines<\/h2>\n<p>\nA useful way to help you identify the different types is to look at your definition each time until you\u2019re comfortable with these concepts. If the lines do something the definition says they cannot, or if they do not have something that the definition requires, then you can more easily identify the lines.<\/p>\n<p>I hope this was helpful. See you next time!<\/p>\n<\/div>\n<div class=\"spoiler\" id=\"PQs-spoiler\">\n<h2 style=\"text-align:center\"><span id=\"Parallel_and_Perpendicular_Lines_Practice_Questions\" class=\"m-toc-anchor\"><\/span>Parallel and Perpendicular Lines 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 \/>\nAt what angle measure do two lines have to intersect to be considered perpendicular lines?<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ\"  id=\"PQ-1-1\">60\u00b0<\/div><div class=\"PQ correct_answer\"  id=\"PQ-1-2\">90\u00b0<\/div><div class=\"PQ\"  id=\"PQ-1-3\">180\u00b0<\/div><div class=\"PQ\"  id=\"PQ-1-4\">270\u00b0<\/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>The correct answer is 90\u00b0. Perpendicular lines are two lines that intersect at a right angle.<\/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 \/>\nWhich of the following is an example of perpendicular lines?<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ\"  id=\"PQ-2-1\">Railroad tracks<\/div><div class=\"PQ\"  id=\"PQ-2-2\">Tree branches<\/div><div class=\"PQ correct_answer\"  id=\"PQ-2-3\">A cross on a church steeple<\/div><div class=\"PQ\"  id=\"PQ-2-4\">Lines on notebook paper<\/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>The correct answer is a cross on a church steeple. A cross is made up of two lines that intersect at a right angle.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2025\/11\/Cross-right-angle.svg\" alt=\"A wooden cross with a black right-angle axis diagram in the top right corner, showing horizontal and vertical arrows.\" width=\"244\" height=\"308\" class=\"aligncenter size-full wp-image-275275\"  role=\"img\" \/><\/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 \/>\nWhich of the following statements is true about parallel lines?<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ correct_answer\"  id=\"PQ-3-1\">They never intersect<\/div><div class=\"PQ\"  id=\"PQ-3-2\">They intersect but not at a right angle<\/div><div class=\"PQ\"  id=\"PQ-3-3\">They intersect at a right angle<\/div><div class=\"PQ\"  id=\"PQ-3-4\">They are the same line<\/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>The correct answer is they never intersect. Parallel lines are two lines in the same plane that never meet.<\/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 \/>\nWhich of the following is an example of parallel lines?<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ\"  id=\"PQ-4-1\">A four-way stoplight<\/div><div class=\"PQ\"  id=\"PQ-4-2\">Tree branches<\/div><div class=\"PQ\"  id=\"PQ-4-3\">A cross on the church steeple<\/div><div class=\"PQ correct_answer\"  id=\"PQ-4-4\">Lines on notebook paper<\/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 correct answer is lines on notebook paper. The horizontal lines never cross, so they are parallel. <\/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 type of lines are these?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.mometrix.com\/academy\/wp-content\/uploads\/2026\/02\/Intersecting-Lines.svg\" alt=\"Two straight arrows cross each other, forming an X shape with arrowheads pointing in four different directions.\" width=\"367\" height=\"159\" class=\"aligncenter size-full wp-image-287684\"  role=\"img\" \/><\/p>\n<\/div>\n\t\t\t\t\t<div class=\"PQ-Choices\"><div class=\"PQ\"  id=\"PQ-5-1\">Parallel<\/div><div class=\"PQ\"  id=\"PQ-5-2\">Perpendicular<\/div><div class=\"PQ correct_answer\"  id=\"PQ-5-3\">Intersecting<\/div><div class=\"PQ\"  id=\"PQ-5-4\">Skew<\/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>The correct answer is intersecting. These two lines cross but not at a right angle, so they are intersecting but not perpendicular.<\/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\/algebra-i\/\">Return to Algebra I Videos<\/a><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Return to Algebra I Videos<\/p>\n","protected":false},"author":1,"featured_media":91024,"parent":0,"menu_order":35,"comment_status":"closed","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":{"0":"post-686","1":"page","2":"type-page","3":"status-publish","4":"has-post-thumbnail","6":"page_category-linear-equations-videos","7":"page_category-math-advertising-group","8":"page_type-video","9":"content_type-practice-questions","10":"subject_matter-math"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/pages\/686","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=686"}],"version-history":[{"count":5,"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/pages\/686\/revisions"}],"predecessor-version":[{"id":280850,"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/pages\/686\/revisions\/280850"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/media\/91024"}],"wp:attachment":[{"href":"https:\/\/www.mometrix.com\/academy\/wp-json\/wp\/v2\/media?parent=686"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}