{"id":269378,"date":"2025-07-24T13:31:56","date_gmt":"2025-07-24T13:31:56","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=269378"},"modified":"2025-07-24T13:31:58","modified_gmt":"2025-07-24T13:31:58","slug":"a-quadrilateral-is-not-a-parallelogram-if-and-only-if","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/24\/a-quadrilateral-is-not-a-parallelogram-if-and-only-if\/","title":{"rendered":"A quadrilateral is NOT a parallelogram if and only if"},"content":{"rendered":"\n<p>A quadrilateral is NOT a parallelogram if and only if <\/p>\n\n\n\n<p>A. the diagonals bisect each other. <\/p>\n\n\n\n<p>B. the opposite angles are congruent. <\/p>\n\n\n\n<p>C. two consecutive angles are supplementary. <\/p>\n\n\n\n<p>D. the non-opposite sides are parallel and congruent.<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\">The correct answer and explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>The correct answer is <strong>C. two consecutive angles are supplementary<\/strong>.<\/p>\n\n\n\n<p>A parallelogram is defined as a quadrilateral in which both pairs of opposite sides are parallel. In a parallelogram, certain properties hold true, such as opposite sides being equal in length, opposite angles being congruent, and the diagonals bisecting each other.<\/p>\n\n\n\n<p>However, if a quadrilateral is not a parallelogram, one of the properties may fail. Specifically, in a non-parallelogram quadrilateral, two consecutive angles are supplementary, meaning that their sum is 180 degrees. This occurs because the consecutive angles form a linear pair, and this property is not exclusive to parallelograms.<\/p>\n\n\n\n<p>The other options refer to properties that are characteristic of parallelograms:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>A. The diagonals bisect each other<\/strong>: This is a defining property of parallelograms, so if a quadrilateral does not have this property, it is not a parallelogram.<\/li>\n\n\n\n<li><strong>B. The opposite angles are congruent<\/strong>: In a parallelogram, opposite angles are always congruent. A quadrilateral that does not have congruent opposite angles cannot be a parallelogram.<\/li>\n\n\n\n<li><strong>D. The non-opposite sides are parallel and congruent<\/strong>: This is a feature of rectangles, squares, and rhombuses, but not a general property of parallelograms. Parallelograms may have opposite sides that are parallel and congruent, but the non-opposite sides being both parallel and congruent would make it a special type of parallelogram, like a rhombus.<\/li>\n<\/ul>\n\n\n\n<p>Therefore, the key feature that distinguishes a non-parallelogram from a parallelogram is the fact that two consecutive angles are supplementary, as stated in option C.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A quadrilateral is NOT a parallelogram if and only if A. the diagonals bisect each other. B. the opposite angles are congruent. C. two consecutive angles are supplementary. D. the non-opposite sides are parallel and congruent. The correct answer and explanation is: The correct answer is C. two consecutive angles are supplementary. A parallelogram is [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-269378","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/269378","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=269378"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/269378\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=269378"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=269378"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=269378"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}