{"id":124906,"date":"2021-09-08T18:37:02","date_gmt":"2021-09-08T13:07:02","guid":{"rendered":"https:\/\/www.kopykitab.com\/blog\/?p=124906"},"modified":"2021-09-08T18:37:06","modified_gmt":"2021-09-08T13:07:06","slug":"rd-sharma-class-9-solutions-chapter-21-exercise-21-1","status":"publish","type":"post","link":"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/","title":{"rendered":"RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 (Updated for 2021-22)"},"content":{"rendered":"\n<p><img class=\"alignnone size-full wp-image-125662\" src=\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/09\/RD-Sharma-Class-9-Solutions-Chapter-21-Exercise-21.1.jpg\" alt=\"RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1\" width=\"1200\" height=\"675\" srcset=\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/09\/RD-Sharma-Class-9-Solutions-Chapter-21-Exercise-21.1.jpg 1200w, https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/09\/RD-Sharma-Class-9-Solutions-Chapter-21-Exercise-21.1-768x432.jpg 768w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/p>\n<p><strong>RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<\/strong>: <span data-sheets-value=\"{&quot;1&quot;:2,&quot;2&quot;:&quot;RD Sharma Solutions Class 9 Maths Chapter 21 Surface Area And Volume of Sphere&quot;}\" data-sheets-userformat=\"{&quot;2&quot;:4284,&quot;5&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;6&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;7&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;8&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;10&quot;:2,&quot;15&quot;:&quot;Arial&quot;}\"><a href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-solutions-class-9-maths-chapter-21-surface-area-and-volume-of-sphere\/\" target=\"_blank\" rel=\"noopener\">RD Sharma Solutions Class 9 Maths Chapter 21 Surface Area And Volume of Sphere<\/a> Exercise 21.1<\/span>\u00a0can be downloaded. These solutions are created by our experts. They provided you with a very beneficial response for your Class 9 exam. The questions are resolved organizably. These solutions are available for free PDF forms that can be saved easily for a long time.<b> <\/b><\/p>\n<ul>\n<li><a href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-for-maths\/\" target=\"_blank\" rel=\"noopener\"><span data-sheets-value=\"{&quot;1&quot;:2,&quot;2&quot;:&quot;RD Sharma Class 9 Maths Solutions&quot;}\" data-sheets-userformat=\"{&quot;2&quot;:4540,&quot;5&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;6&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;7&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;8&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;10&quot;:2,&quot;11&quot;:0,&quot;15&quot;:&quot;Arial&quot;}\">RD Sharma Class 9 Maths Solutions<\/span><\/a><\/li>\n<\/ul>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_47_1 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"ez-toc-toggle-icon-1\"><label for=\"item-69d81762a01e7\" aria-label=\"Table of Content\"><span style=\"display: flex;align-items: center;width: 35px;height: 30px;justify-content: center;direction:ltr;\"><svg style=\"fill: #000000;color:#000000\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #000000;color:#000000\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/label><input  type=\"checkbox\" id=\"item-69d81762a01e7\"><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 eztoc-visibility-hide-by-default' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/#download-rd-sharma-class-9-solutions-chapter-21-exercise-211\" title=\"Download RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1\">Download RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/#access-rd-sharma-class-9-solutions-chapter-21-exercise-211\" title=\"Access RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1\">Access RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<\/a><ul class='ez-toc-list-level-3'><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/#faq-rd-sharma-class-9-solutions-chapter-21-exercise-211\" title=\"FAQ: RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1\">FAQ: RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/#can-i-download-rd-sharma-class-9-solutions-chapter-21-exercise-211-pdf-free\" title=\"Can I download RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 PDF free?\">Can I download RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 PDF free?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/#can-i-open-rd-sharma-class-9-solutions-chapter-21-exercise-211-pdf-on-my-smartphone\" title=\"Can I open RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 PDF on my smartphone?\">Can I open RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 PDF on my smartphone?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/#is-rd-sharma-enough-for-class-12-maths\" title=\"Is RD Sharma enough for Class 12 Maths?\">Is RD Sharma enough for Class 12 Maths?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/#what-are-the-benefits-of-studying-from-rd-sharma-solutions-class-12\" title=\"What are the benefits of studying from RD Sharma Solutions Class 12?\">What are the benefits of studying from RD Sharma Solutions Class 12?<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"download-rd-sharma-class-9-solutions-chapter-21-exercise-211\"><\/span>Download RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u00a0<\/p>\n<div id=\"example1\" style=\"text-align: justify;\">\u00a0<\/div>\n<p style=\"text-align: justify;\"><style>\n.pdfobject-container { height: 500px;}<br \/>\n.pdfobject { border: 1px solid #666; }<br \/>\n<\/style><\/p>\n<p style=\"text-align: justify;\"><script src=\"https:\/\/www.kopykitab.com\/_utility\/js\/pdfobject.min.js\"><\/script><br \/><script>PDFObject.embed(\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/09\/21.1.pdf\", \"#example1\");<\/script><\/p>\n<p><a href=\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/09\/21.1.pdf\">RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<\/a><\/p>\n<h2><span class=\"ez-toc-section\" id=\"access-rd-sharma-class-9-solutions-chapter-21-exercise-211\"><\/span>Access RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Question 1.<br \/>Find the surface area of a sphere of radius.<br \/>(i) 10.5 cm<br \/>(ii) 5.6 cm<br \/>(iii) 14 cm<br \/>Solution:<br \/>In a sphere,<br \/>(i) Radius (r) = 10.5 cm<br \/>Surface area = 4\u03c0r<sup>2<\/sup><br \/><img src=\"https:\/\/farm2.staticflickr.com\/1909\/45597193512_5a28b7b0cb_o.png\" alt=\"RD Sharma Class 9 Chapter 21 Surface Areas and Volume of a Sphere\" width=\"284\" height=\"542\" \/><\/p>\n<p>Question 2.<br \/>Find the surface area of a sphere of diameter<br \/>(i) 14 cm<br \/>(ii) 21 cm<br \/>(iii) 3.5 cm<br \/>Solution:<br \/>(i) Diameter of a sphere = 14 cm<br \/>Radius (r) =\u00a0<span id=\"MathJax-Element-1-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-1\" class=\"math\"><span id=\"MathJax-Span-2\" class=\"mrow\"><span id=\"MathJax-Span-3\" class=\"mfrac\"><span id=\"MathJax-Span-4\" class=\"mn\">14<\/span><span id=\"MathJax-Span-5\" class=\"mn\">2<\/span><\/span><\/span><\/span><\/span>\u00a0= 7 cm<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1913\/31775266318_30bf7a2684_o.png\" alt=\"RD Sharma Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere\" width=\"313\" height=\"493\" \/><\/p>\n<p>Question 3.<br \/>Find the total surface area of a hemisphere and a solid hemisphere each of radius 10 cm. [Use \u03c0 = 3.14]<br \/>Solution:<br \/>(i) Radius of hemisphere = 10 cm<br \/>\u2234 Total surface area of hemisphere = 2\u03c0r<sup>2<\/sup><br \/>= 2 x 3.14 x 10 x 10 cm<sup>2<\/sup><br \/>= 628 cm<sup>2<\/sup><br \/>(ii) Total surface area of solid hemisphere<br \/>= 3\u03c0r<sup>2<\/sup>\u00a0= 3 x 3.14 x 10 x 10 cm<sup>2<\/sup><br \/>= 942 cm<sup>2<\/sup><\/p>\n<p>Question 4.<br \/>The surface area of a sphere in 5544 cm<sup>2<\/sup>, find the diameter.<br \/>Solution:<br \/>Let r be the radius of a sphere, then Surface area = 4\u03c0r<sup>2<\/sup><br \/><img src=\"https:\/\/farm2.staticflickr.com\/1961\/45597192992_3e88360e6a_o.png\" alt=\"RD Sharma Solutions Class 9 Chapter 21 Surface Areas and Volume of a Sphere\" width=\"249\" height=\"143\" \/><br \/><img src=\"https:\/\/farm2.staticflickr.com\/1979\/31775266178_5082224a6f_o.png\" alt=\"RD Sharma Class 9 PDF Chapter 21 Surface Areas and Volume of a Sphere\" width=\"331\" height=\"51\" \/><\/p>\n<div>Question 5.<br \/>A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin-plating it on the inside at the rate of \u20b94 per 100 cm<sup>2<\/sup>. [NCERT]<br \/>Solution:<br \/>Inner diameter of a hemispherical bowl = 10.5 cm<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1912\/45597192822_3e6cee459a_o.png\" alt=\"Surface Areas and Volume of a Sphere Class 9 RD Sharma Solutions\" width=\"322\" height=\"358\" \/><\/div>\n<div>Question 6.<br \/>The dome of a building is in the form of a hemisphere. Its radius is 63 dm. Find the cost of painting it at the rate of \u20b92 per sq. m.<br \/>Solution:<br \/>Radius of dome (hemispherical) = 63 dm<br \/>Area of curved surface<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1902\/31775266128_6f7e71678d_o.png\" alt=\"RD Sharma Class 9 Solution Chapter 21 Surface Areas and Volume of a Sphere\" width=\"307\" height=\"187\" \/><\/div>\n<div>\n<p>Question 7.<br \/>Assuming the earth to be a sphere of radius 6370 km, how many square kilometres is area of the land, if three-fourth of the earth\u2019s surface is covered by water?<br \/>Solution:<br \/>Radius of earth (sphere) = 6370 km<br \/>Water on the earth =\u00a0<span id=\"MathJax-Element-2-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-6\" class=\"math\"><span id=\"MathJax-Span-7\" class=\"mrow\"><span id=\"MathJax-Span-8\" class=\"mfrac\"><span id=\"MathJax-Span-9\" class=\"mn\">3<\/span><span id=\"MathJax-Span-10\" class=\"mn\">4<\/span><\/span><\/span><\/span><\/span>\u00a0% total area<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1959\/45597192542_2d167d7590_o.png\" alt=\"Class 9 RD Sharma Solutions Chapter 21 Surface Areas and Volume of a Sphere\" width=\"290\" height=\"211\" \/><\/p>\n<p>Question 8.<br \/>A cylinder of same height and radius is placed on the top of a hemisphere. Find the curved surface area of the shape if the length of the shape be 7 cm.<br \/>Solution:<br \/>Total height of the so formed shape = 7 cm<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1944\/44733444405_b557f75f49_o.png\" alt=\"Class 9 Maths Chapter 21 Surface Areas and Volume of a Sphere RD Sharma Solutions\" width=\"304\" height=\"451\" \/><\/p>\n<p>Question 9.<br \/>The diameter of the moon is approximately one fourth of the diameter of the earth. Find the ratio of their surface areas.<br \/>Solution:<br \/>Diameter of moon =\u00a0<span id=\"MathJax-Element-3-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-11\" class=\"math\"><span id=\"MathJax-Span-12\" class=\"mrow\"><span id=\"MathJax-Span-13\" class=\"mfrac\"><span id=\"MathJax-Span-14\" class=\"mn\">1<\/span><span id=\"MathJax-Span-15\" class=\"mn\">4<\/span><\/span><\/span><\/span><\/span>\u00a0of diameter of earth<br \/>Let radius of earth = r km<br \/>Then radius of moon =\u00a0<span id=\"MathJax-Element-4-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-16\" class=\"math\"><span id=\"MathJax-Span-17\" class=\"mrow\"><span id=\"MathJax-Span-18\" class=\"mfrac\"><span id=\"MathJax-Span-19\" class=\"mn\">1<\/span><span id=\"MathJax-Span-20\" class=\"mn\">4<\/span><\/span><\/span><\/span><\/span>\u00a0r km<br \/>Now surface area of earth = 4\u03c0r<sup>2<\/sup><br \/><img src=\"https:\/\/farm2.staticflickr.com\/1963\/45597192272_281f30064e_o.png\" alt=\"RD Sharma Book Class 9 PDF Free Download Chapter 21 Surface Areas and Volume of a Sphere\" width=\"330\" height=\"254\" \/><\/p>\n<p>Question 10.<br \/>A hemi-spherical dome of a building needs to be painted. If the circumference of the base of the dome is 17.6 m, find the cost of painting it, given the cost of painting is \u20b95 per 100 cm<sup>2<\/sup>. [NCERT]<br \/>Solution:<br \/>Circumference of the base of dome (r) = 17.6 m<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1940\/44733444275_d71934993b_o.png\" alt=\"RD Sharma Class 9 Book Chapter 21 Surface Areas and Volume of a Sphere\" width=\"312\" height=\"337\" \/><br \/><img src=\"https:\/\/farm2.staticflickr.com\/1959\/31775265958_c97bd60aee_o.png\" alt=\"Surface Areas and Volume of a Sphere With Solutions PDF RD Sharma Class 9 Solutions\" width=\"284\" height=\"75\" \/><\/p>\n<p>Question 11.<br \/>A wooden toy is in the form of a cone surmounted on a hemisphere. The diameter of the base of the cone is 16 cm and its height is 15 cm. Find the cost of painting the toy at \u20b97 per 100 cm<sup>2<\/sup>.<br \/>Solution:<br \/>Diameter of toy = 16 cm<br \/>Radius (r) =\u00a0<span id=\"MathJax-Element-5-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-21\" class=\"math\"><span id=\"MathJax-Span-22\" class=\"mrow\"><span id=\"MathJax-Span-23\" class=\"mfrac\"><span id=\"MathJax-Span-24\" class=\"mn\">16<\/span><span id=\"MathJax-Span-25\" class=\"mn\">2<\/span><\/span><\/span><\/span><\/span>\u00a0= 8 cm<br \/>Height of conical part (h) = 15 cm<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1964\/45597191882_7319722cc7_o.png\" alt=\"RD Sharma Class 9 Maths Book Questions Chapter 21 Surface Areas and Volume of a Sphere\" width=\"318\" height=\"633\" \/><br \/><img src=\"https:\/\/farm2.staticflickr.com\/1966\/31775265888_b0c09b88cf_o.png\" alt=\"RD Sharma Mathematics Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere\" width=\"322\" height=\"211\" \/><\/p>\n<p>Question 12.<br \/>A storage tank consists of a circular cylinder with a hemisphere adjoined on either end. If the external diameter of the cylinder be 1.4 m and its length be 8 m, find the cost of painting it on the outside at the rate of \u20b910 per m<sup>2<\/sup>.<br \/>Solution:<br \/>Diameter of the tank = 1.4 m<br \/>\u2234 Radius (r) =\u00a0<span id=\"MathJax-Element-6-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-26\" class=\"math\"><span id=\"MathJax-Span-27\" class=\"mrow\"><span id=\"MathJax-Span-28\" class=\"mfrac\"><span id=\"MathJax-Span-29\" class=\"mn\">1.4<\/span><span id=\"MathJax-Span-30\" class=\"mn\">2<\/span><\/span><\/span><\/span><\/span>\u00a0m = 0.7 m<br \/>and height of cylindrical portion = 8m<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1954\/44733443935_b6489262ea_o.png\" alt=\"RD Sharma Math Solution Class 9 Chapter 21 Surface Areas and Volume of a Sphere\" width=\"307\" height=\"464\" \/><br \/><img src=\"https:\/\/farm2.staticflickr.com\/1958\/31775265828_7378731bca_o.png\" alt=\"RD Sharma Class 9 Questions Chapter 21 Surface Areas and Volume of a Sphere\" width=\"341\" height=\"191\" \/><\/p>\n<p>Question 13.<br \/>The front compound wall of a house is decorated by wooden spheres of diameter 21 cm, placed on small supports as shown in the figure. Eight such spheres are used for this purpose, and are to be painted silver. Each support is a cylinder of radius 1.5 cm and height 7 cm and is to be painted black. Find the cost of paint required if silver paint costs 25 paise per cm<sup>2<\/sup>\u00a0and black paint costs 5 paise per cm<sup>2<\/sup>. [NCERT]<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1942\/31775265778_b0297abdb6_o.png\" alt=\"Class 9 RD Sharma Solutions Chapter 21 Surface Areas and Volume of a Sphere\" width=\"208\" height=\"153\" \/><br \/>Solution:<br \/>Diameter of each spheres = 21 cm<br \/>\u2234 Radius (R) =\u00a0<span id=\"MathJax-Element-7-Frame\" class=\"MathJax\" tabindex=\"0\"><span id=\"MathJax-Span-31\" class=\"math\"><span id=\"MathJax-Span-32\" class=\"mrow\"><span id=\"MathJax-Span-33\" class=\"mfrac\"><span id=\"MathJax-Span-34\" class=\"mn\">21<\/span><span id=\"MathJax-Span-35\" class=\"mn\">2<\/span><\/span><\/span><\/span><\/span>\u00a0cm<br \/>Radius of each cylinder (r) = 1.5 cm<br \/>and height (h) = 7 cm<br \/><img src=\"https:\/\/farm2.staticflickr.com\/1937\/31775265718_5b3654ee3a_o.png\" alt=\"Class 9 Maths Chapter 21 Surface Areas and Volume of a Sphere RD Sharma Solutions Ex 21.1\" width=\"155\" height=\"188\" \/><br \/>Now surface area of one sphere = 4\u03c0R<sup>2<\/sup><br \/><img src=\"https:\/\/farm2.staticflickr.com\/1938\/44733443645_1a4f335ddd_o.png\" alt=\"RD Sharma Book Class 9 PDF Free Download Chapter 21 Surface Areas and Volume of a Sphere\" width=\"352\" height=\"686\" \/><\/p>\n<p>We have included all the information regarding <a href=\"https:\/\/cbse.nic.in\/\" target=\"_blank\" rel=\"noopener\">CBSE<\/a> RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<span data-sheets-value=\"{&quot;1&quot;:2,&quot;2&quot;:&quot;RD Sharma Class 9 Solutions Chapter 20 Exercise 20.1&quot;}\" data-sheets-userformat=\"{&quot;2&quot;:4540,&quot;5&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;6&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;7&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;8&quot;:{&quot;1&quot;:[{&quot;1&quot;:2,&quot;2&quot;:0,&quot;5&quot;:[null,2,0]},{&quot;1&quot;:0,&quot;2&quot;:0,&quot;3&quot;:3},{&quot;1&quot;:1,&quot;2&quot;:0,&quot;4&quot;:1}]},&quot;10&quot;:2,&quot;11&quot;:0,&quot;15&quot;:&quot;Arial&quot;}\">. If you have any query feel free to ask in the comment section.\u00a0<\/span><\/p>\n<h3><span class=\"ez-toc-section\" id=\"faq-rd-sharma-class-9-solutions-chapter-21-exercise-211\"><\/span>FAQ: RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<\/div>\n\n\n<div id=\"rank-math-faq\" class=\"rank-math-block\">\n<div class=\"rank-math-list \">\n<div id=\"faq-question-1630934256369\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \"><span class=\"ez-toc-section\" id=\"can-i-download-rd-sharma-class-9-solutions-chapter-21-exercise-211-pdf-free\"><\/span>Can I download RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 PDF free?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<div class=\"rank-math-answer \">\n\n<p>Yes, you can download RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 PDF free.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"faq-question-1630934279804\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \"><span class=\"ez-toc-section\" id=\"can-i-open-rd-sharma-class-9-solutions-chapter-21-exercise-211-pdf-on-my-smartphone\"><\/span>Can I open RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 PDF on my smartphone?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<div class=\"rank-math-answer \">\n\n<p>Yes, you can open RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 PDF on any device.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"faq-question-1630934281954\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \"><span class=\"ez-toc-section\" id=\"is-rd-sharma-enough-for-class-12-maths\"><\/span>Is RD Sharma enough for Class 12 Maths?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<div class=\"rank-math-answer \">\n\n<p>RD Sharma is a good book that gives you thousands of questions to practice.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"faq-question-1630934285701\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \"><span class=\"ez-toc-section\" id=\"what-are-the-benefits-of-studying-from-rd-sharma-solutions-class-12\"><\/span>What are the benefits of studying from RD Sharma Solutions Class 12?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<div class=\"rank-math-answer \">\n\n<p>By practicing these solutions, students can earn higher academic grades. Our experts solve these solutions with utmost accuracy to help students in their studies.<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1: RD Sharma Solutions Class 9 Maths Chapter 21 Surface Area And Volume of Sphere Exercise 21.1\u00a0can be downloaded. These solutions are created by our experts. They provided you with a very beneficial response for your Class 9 exam. The questions are resolved organizably. These solutions are &#8230; <a title=\"RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 (Updated for 2021-22)\" class=\"read-more\" href=\"https:\/\/www.kopykitab.com\/blog\/rd-sharma-class-9-solutions-chapter-21-exercise-21-1\/\" aria-label=\"More on RD Sharma Class 9 Solutions Chapter 21 Exercise 21.1 (Updated for 2021-22)\">Read more<\/a><\/p>\n","protected":false},"author":244,"featured_media":125662,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":""},"categories":[73719],"tags":[3085,76794,76795],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/posts\/124906"}],"collection":[{"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/users\/244"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/comments?post=124906"}],"version-history":[{"count":4,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/posts\/124906\/revisions"}],"predecessor-version":[{"id":125668,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/posts\/124906\/revisions\/125668"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/media\/125662"}],"wp:attachment":[{"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/media?parent=124906"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/categories?post=124906"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/tags?post=124906"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}