{"id":453,"date":"2022-04-12T10:37:44","date_gmt":"2022-04-12T10:37:44","guid":{"rendered":"http:\/\/7thclass.deltapublications.in\/?page_id=453"},"modified":"2025-11-10T07:21:35","modified_gmt":"2025-11-10T07:21:35","slug":"w-7-semicircles-calculate-area-perimeter-radius-and-diameter","status":"publish","type":"page","link":"https:\/\/7thclass.deltapublications.in\/index.php\/w-7-semicircles-calculate-area-perimeter-radius-and-diameter\/","title":{"rendered":"W.7 Semicircles: calculate area, perimeter, radius and diameter"},"content":{"rendered":"\n<h2 class=\"wp-block-heading has-text-align-center has-text-color\" style=\"color:#00056d;text-transform:uppercase\"><strong> Semicircles: calculate area, perimeter, radius and diameter<\/strong><\/h2>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\">\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\">\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\">\n<div style=\"position: relative; width: 100%; height: 0; padding-top: 56.2500%;\n padding-bottom: 0; box-shadow: 0 2px 8px 0 rgba(63,69,81,0.16); margin-top: 1.6em; margin-bottom: 0.9em; overflow: hidden;\n border-radius: 8px; will-change: transform;\">\n  <iframe loading=\"lazy\" style=\"position: absolute; width: 100%; height: 100%; top: 0; left: 0; border: none; padding: 0;margin: 0;\"\n    src=\"https:\/\/www.canva.com\/design\/DAG3JYe6Nks\/gVx7TlzVSyrs4VRlerrLVw\/watch?embed\" allowfullscreen=\"allowfullscreen\" allow=\"fullscreen\">\n  <\/iframe>\n<\/div>\n<a href=\"https:&#x2F;&#x2F;www.canva.com&#x2F;design&#x2F;DAG3JYe6Nks&#x2F;gVx7TlzVSyrs4VRlerrLVw&#x2F;watch?utm_content=DAG3JYe6Nks&amp;utm_campaign=designshare&amp;utm_medium=embeds&amp;utm_source=link\" target=\"_blank\" rel=\"noopener\">Design<\/a> by Delta publications\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#74008b\"><strong>key notes :<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table has-normal-font-size\"><table class=\"has-text-color has-link-color has-fixed-layout\" style=\"color:#000060\"><tbody><tr><td><strong>Key Definitions<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Perimeter<\/strong>: The total distance around a closed shape (boundary length).<\/li>\n\n\n\n<li><strong>Area<\/strong>: The surface covered by a closed shape (space inside).<\/li>\n\n\n\n<li><strong>Radius (r)<\/strong>: Distance from the center of a circle to its boundary.<\/li>\n\n\n\n<li><strong>Diameter (d)<\/strong>: Longest chord of a circle, passing through the center. d=2r and r=d\/2\u200b<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table has-normal-font-size\"><table class=\"has-text-color has-link-color has-fixed-layout\" style=\"color:#000060\"><tbody><tr><td><strong><strong>Formulas<\/strong><\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading has-normal-font-size\"><strong>(A) Rectangle<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Area: A=L\u00d7B<\/li>\n\n\n\n<li>Perimeter: P=2(L+B)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading has-normal-font-size\">(B) <strong>Square<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Area: A=side<sup>2<\/sup><\/li>\n\n\n\n<li>Perimeter: P=4\u00d7side<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading has-normal-font-size\"><strong>(C) Triangle<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Area: A=1\/2\u00d7base\u00d7height<\/li>\n\n\n\n<li>Perimeter: P=a+b+c<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading has-normal-font-size\"><strong>(D) Circle<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Circumference (Perimeter): C=2\u03c0r or C=\u03c0d<\/li>\n\n\n\n<li>Area: A=\u03c0r<sup>2<\/sup><\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table has-normal-font-size\"><table class=\"has-text-color has-link-color has-fixed-layout\" style=\"color:#000060\"><tbody><tr><td><strong>Examples<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading has-normal-font-size\"><strong>Example 1: Rectangle<\/strong><\/h3>\n\n\n\n<p>Length = 12 cm, Breadth = 8 cm<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Area = 12\u00d78=96\u2009cm<sup>2<\/sup><\/li>\n\n\n\n<li>Perimeter = 2(12+8)=40\u2009cm<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading has-normal-font-size\"><strong>Example 2: Square<\/strong><\/h3>\n\n\n\n<p>Side = 15 m<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Area = 15<sup>2<\/sup>=225\u2009m<sup>2<\/sup><\/li>\n\n\n\n<li>Perimeter = 4\u00d715=60\u2009m<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading has-normal-font-size\"><strong>Example 3: Triangle<\/strong><\/h3>\n\n\n\n<p>Base = 10 cm, Height = 8 cm, Other two sides = 7 cm and 9 cm<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Area = 1\/2\u00d710\u00d78=40\u2009cm<sup>2<\/sup><\/li>\n\n\n\n<li>Perimeter = 10+7+9=26\u2009cm<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading has-normal-font-size\"><strong>Example 4: Circle<\/strong><\/h3>\n\n\n\n<p>Radius = 7 cm<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Diameter = 2\u00d77=14\u2009cm<\/li>\n\n\n\n<li>Circumference = 2\u00d7227\u00d77=44\u2009cm<\/li>\n\n\n\n<li>Area = 227\u00d77\u00d77=154\u2009cm<sup>2<\/sup><\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table has-normal-font-size\"><table class=\"has-text-color has-link-color has-fixed-layout\" style=\"color:#000060\"><tbody><tr><td><strong><strong>Important Points<\/strong><\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Perimeter<\/strong> is always in linear units (cm, m, km).<\/li>\n\n\n\n<li><strong>Area<\/strong> is always in square units (cm\u00b2, m\u00b2, km\u00b2).<\/li>\n\n\n\n<li>For circles, check if radius or diameter is given.<\/li>\n\n\n\n<li>Use \u03c0=3.14 or 22\/7.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table has-normal-font-size\"><table class=\"has-text-color has-link-color has-fixed-layout\" style=\"color:#000060\"><tbody><tr><td><strong><strong><strong>Practice Questions<\/strong><\/strong><\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<ol class=\"wp-block-list\">\n<li>A rectangle has length 18 cm and breadth 12 cm. Find its area and perimeter.<\/li>\n\n\n\n<li>The side of a square is 25 m. Find its area and perimeter.<\/li>\n\n\n\n<li>A triangle has base 15 cm, height 12 cm, and the other two sides are 10 cm and 13 cm. Find its area and perimeter.<\/li>\n\n\n\n<li>A circular park has a diameter of 28 m. Find its radius, circumference, and area.<\/li>\n\n\n\n<li>The circumference of a circle is 62.8 cm. Find its radius and area.<\/li>\n<\/ol>\n\n\n\n<p class=\"has-text-align-center has-text-color has-huge-font-size\" style=\"color:#105000\"><strong>Learn with an example<\/strong><\/p>\n\n\n\n<div class=\"wp-block-group has-primary-color has-text-color has-background has-normal-font-size\" style=\"background-color:#f7d4f8\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-group has-primary-color has-background-background-color has-text-color has-background\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<p class=\"has-text-color\" style=\"color:#b00012\">\u25b6\ufe0f <strong>The&nbsp;radius of a semicircle is&nbsp;1&nbsp;kilometre. What is the semicircle&#8217;s&nbsp;perimeter?<\/strong><\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km.png\" alt=\"\" class=\"wp-image-10298\" style=\"aspect-ratio:1;width:294px;height:auto\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km.png 500w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-300x300.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-150x150.png 150w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-400x400.png 400w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/figure><\/div>\n\n\n<p>Use&nbsp;3.14 for&nbsp;\u200b\ud835\udf0b.&nbsp;<\/p>\n\n\n\n<p>______ kilometres<\/p>\n<\/div><\/div>\n\n\n\n<p>The&nbsp;radius is&nbsp;1&nbsp;kilometre. Replace&nbsp;r&nbsp;by&nbsp;1&nbsp;in the&nbsp;formula.<\/p>\n\n\n\n<p>p = 2\u200b\ud835\udf0br\/2 + 2r<\/p>\n\n\n\n<p>\u2248 2 . 3 . 14 . 1 \/ 2 + 2 . 1<\/p>\n\n\n\n<p>\u2248 6 . 28 \/ 2 + 2<\/p>\n\n\n\n<p>\u2248 3.14+2<\/p>\n\n\n\n<p>\u2248 5 . 14<\/p>\n\n\n\n<p>The perimeter is about 5.14 kilometres.<\/p>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group has-primary-color has-text-color has-background has-normal-font-size\" style=\"background-color:#fad5d5\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-group has-primary-color has-background-background-color has-text-color has-background\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<p class=\"has-text-color\" style=\"color:#b00012\">\u25b6\ufe0f<strong> The&nbsp;diameter of a semicircle is&nbsp;6&nbsp;kilometres. What is the semicircle&#8217;s&nbsp;radius?<\/strong><\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-1.png\" alt=\"\" class=\"wp-image-10299\" style=\"aspect-ratio:1;width:294px;height:auto\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-1.png 500w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-1-300x300.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-1-150x150.png 150w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-1-400x400.png 400w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/figure><\/div>\n\n\n<p>______ &nbsp;kilometres<\/p>\n<\/div><\/div>\n\n\n\n<p>The&nbsp;diameter is equal to&nbsp;6&nbsp;kilometres. Replace&nbsp;d&nbsp;by&nbsp;6&nbsp;in the&nbsp;formula.<\/p>\n\n\n\n<p>d = 2r<\/p>\n\n\n\n<p>6 = 2r<\/p>\n\n\n\n<p>6 \u00f7 2 = r<\/p>\n\n\n\n<p>3 = r<\/p>\n\n\n\n<p>The radius is 3 kilometres.<\/p>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group has-primary-color has-text-color has-background has-normal-font-size\" style=\"background-color:#f2e2fc\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-group has-primary-color has-background-background-color has-text-color has-background\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<p class=\"has-text-color\" style=\"color:#b00012\">\u25b6\ufe0f<strong> The&nbsp;diameter of a semicircleis&nbsp;6&nbsp;kilometres. What is the semicircle&#8217;s&nbsp;perimeter?<\/strong><\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-2.png\" alt=\"\" class=\"wp-image-10300\" style=\"aspect-ratio:1;width:292px;height:auto\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-2.png 500w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-2-300x300.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-2-150x150.png 150w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/12\/r-1-km-2-400x400.png 400w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/figure><\/div>\n\n\n<p>Use&nbsp;3.14 for&nbsp;\u200b\ud835\udf0b.&nbsp;<\/p>\n\n\n\n<p>_______ kilometres<\/p>\n<\/div><\/div>\n\n\n\n<p>The&nbsp;diameter is&nbsp;6&nbsp;kilometres. Replace&nbsp;d&nbsp;by&nbsp;6&nbsp;in the&nbsp;formula.<\/p>\n\n\n\n<p>p = \ud835\udf0bd \/ 2 + d<\/p>\n\n\n\n<p>\u2248 3 . 14 . 6 \/ 2 + 6<\/p>\n\n\n\n<p>\u2248 18 . 84 \/2 + 6<\/p>\n\n\n\n<p>\u22489.42+6<\/p>\n\n\n\n<p>\u224815.42<\/p>\n\n\n\n<p>The perimeter is about 15.42 kilometres.<\/p>\n<\/div><\/div>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#d90000\">Let&#8217;s practice!\ud83d\udd8a\ufe0f<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/wordwall.net\/play\/101657\/928\/669\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-2-131.png\" alt=\"\" class=\"wp-image-6890\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-2-131.png 500w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-2-131-300x300.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-2-131-150x150.png 150w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-2-131-400x400.png 400w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/wordwall.net\/play\/36129\/948\/902\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-1-1-133.png\" alt=\"\" class=\"wp-image-6891\" srcset=\"https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-1-1-133.png 500w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-1-1-133-300x300.png 300w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-1-1-133-150x150.png 150w, https:\/\/7thclass.deltapublications.in\/wp-content\/uploads\/2023\/05\/Worksheet-1-1-1-133-400x400.png 400w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><\/figure>\n<\/div>\n<\/div>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Semicircles: calculate area, perimeter, radius and diameter Design by Delta publications key notes : Key Definitions Formulas (A) Rectangle (B) Square (C) Triangle (D) Circle Examples Example 1: Rectangle Length = 12 cm, Breadth = 8 cm Example 2: Square Side = 15 m Example 3: Triangle Base = 10 cm, Height = 8 cm,<a class=\"more-link\" href=\"https:\/\/7thclass.deltapublications.in\/index.php\/w-7-semicircles-calculate-area-perimeter-radius-and-diameter\/\">Continue reading <span class=\"screen-reader-text\">&#8220;W.7 Semicircles: calculate area, perimeter, radius and diameter&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"footnotes":""},"class_list":["post-453","page","type-page","status-publish","hentry","entry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/453","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/comments?post=453"}],"version-history":[{"count":20,"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/453\/revisions"}],"predecessor-version":[{"id":17563,"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/453\/revisions\/17563"}],"wp:attachment":[{"href":"https:\/\/7thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/media?parent=453"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}