{"id":252343,"date":"2025-07-11T08:43:30","date_gmt":"2025-07-11T08:43:30","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=252343"},"modified":"2025-07-11T08:43:38","modified_gmt":"2025-07-11T08:43:38","slug":"the-distance-around-the-outside-of-a-circle-is-called-the-circumference","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/11\/the-distance-around-the-outside-of-a-circle-is-called-the-circumference\/","title":{"rendered":"The distance around the outside of a circle is called the circumference"},"content":{"rendered":"\n<p>The distance around the outside of a circle is called the circumference. The distance from the center of the circle to any point on the circle is called the radius. The number of square units needed to cover the inside of a circle is called the area. The distance across a circle through its center is called the diameter. Write the following formulas: 5. Circumference when the radius is given: C = 2\u00cf\u20acr 6. Circumference when the diameter is given: C = \u00cf\u20acd 7. Area of a circle: A = \u00cf\u20acr^2 Find the circumference of each circle; Round to the nearest tenth. (Show your work and don&#8217;t forget to label your answer): 8. Radius = 8 cm: C = 2\u00cf\u20ac(8) = 16\u00cf\u20ac \u00e2\u2030\u02c6 50.3 cm 9. Diameter = 17 m: C = \u00cf\u20ac(17) \u00e2\u2030\u02c6 53.4 m Find the area of each circle: Round to the nearest tenth: (Show your work and don&#8217;t forget to label your answer): 10. Radius = 3 in: A = \u00cf\u20ac(3)^2 \u00e2\u2030\u02c6 28.3 in^2 11. Diameter = 9 ft: A = \u00cf\u20ac(9\/2)^2 \u00e2\u2030\u02c6 63.6 ft^2<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p><strong>5. Circumference when the radius is given<\/strong><br>Formula: C = 2\u03c0r<\/p>\n\n\n\n<p><strong>6. Circumference when the diameter is given<\/strong><br>Formula: C = \u03c0d<\/p>\n\n\n\n<p><strong>7. Area of a circle<\/strong><br>Formula: A = \u03c0r\u00b2<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>8. Radius = 8 cm<\/strong><\/h3>\n\n\n\n<p><strong>C = 2\u03c0r<\/strong><br>= 2 \u00d7 \u03c0 \u00d7 8<br>= 16\u03c0 \u2248 16 \u00d7 3.1416 \u2248 50.3 cm<br><strong>Answer: 50.3 cm<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>9. Diameter = 17 m<\/strong><\/h3>\n\n\n\n<p><strong>C = \u03c0d<\/strong><br>= \u03c0 \u00d7 17 \u2248 3.1416 \u00d7 17 \u2248 53.4 m<br><strong>Answer: 53.4 m<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>10. Radius = 3 in<\/strong><\/h3>\n\n\n\n<p><strong>A = \u03c0r\u00b2<\/strong><br>= \u03c0 \u00d7 3\u00b2 = \u03c0 \u00d7 9 \u2248 3.1416 \u00d7 9 \u2248 28.3 in\u00b2<br><strong>Answer: 28.3 in\u00b2<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>11. Diameter = 9 ft<\/strong><\/h3>\n\n\n\n<p>Radius = diameter \u00f7 2 = 9 \u00f7 2 = 4.5 ft<br><strong>A = \u03c0r\u00b2<\/strong><br>= \u03c0 \u00d7 (4.5)\u00b2 = \u03c0 \u00d7 20.25 \u2248 3.1416 \u00d7 20.25 \u2248 63.6 ft\u00b2<br><strong>Answer: 63.6 ft\u00b2<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation <\/h3>\n\n\n\n<p>Understanding the geometry of a circle is essential in many areas of math and real life. Four key terms related to a circle include the <strong>radius<\/strong>, <strong>diameter<\/strong>, <strong>circumference<\/strong>, and <strong>area<\/strong>. The <strong>radius<\/strong> is the distance from the center to any point on the circle. The <strong>diameter<\/strong> is twice the length of the radius, stretching from one point on the circle to another, passing through the center. The <strong>circumference<\/strong> is the perimeter or distance around the circle. The <strong>area<\/strong> measures the surface inside the circle in square units.<\/p>\n\n\n\n<p>To find the <strong>circumference<\/strong>, we use two formulas based on what is known:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>If the <strong>radius<\/strong> is given, use <strong>C = 2\u03c0r<\/strong><\/li>\n\n\n\n<li>If the <strong>diameter<\/strong> is given, use <strong>C = \u03c0d<\/strong><\/li>\n<\/ul>\n\n\n\n<p>In both cases, \u03c0 (pi) is approximately 3.1416. This constant represents the ratio of a circle\u2019s circumference to its diameter.<\/p>\n\n\n\n<p>To calculate the <strong>area<\/strong>, we use the formula <strong>A = \u03c0r\u00b2<\/strong>, where r is the radius. This formula comes from the concept of how many square units fill the inside of the circle.<\/p>\n\n\n\n<p>When doing calculations, it is important to follow the order of operations, squaring the radius before multiplying by \u03c0. Answers are usually rounded to the nearest tenth unless instructed otherwise, and units must be included, such as cm, m, in\u00b2, or ft\u00b2, depending on the measurement used.<\/p>\n\n\n\n<p>These basic circle formulas help solve many problems in geometry, engineering, and design<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/07\/learnexams-banner6-227.jpeg\" alt=\"\" class=\"wp-image-252344\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>The distance around the outside of a circle is called the circumference. The distance from the center of the circle to any point on the circle is called the radius. The number of square units needed to cover the inside of a circle is called the area. The distance across a circle through its center [&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-252343","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/252343","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=252343"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/252343\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=252343"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=252343"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=252343"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}