Example 15 - The height and slant height of a cone are 21 cm - Examples

  1. Chapter 13 Class 9 Surface Areas and Volumes
  2. Serial order wise
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Example 15 The height and the slant height of a cone are 21 cm and 28 cm respectively. Find the volume of the cone. Volume of the come = 1/3 ๐œ‹๐‘Ÿ2โ„Ž Given slant height = l = 28 cm Height of cone = h = 21 cm Let radius of cone = r cm We know that l2 = h2 + r2 282 = 212 + r2 282 โ€“ 212 = r2 r2 = 282 โ€“ 212 r2 = (28 โ€“ 21) (28 + 21) r2 = (7) (49) r = โˆš("7(49)" ) r = โˆš("7(7)2" ) r = 7โˆš7cm So, Volume of the come = 1/3 ๐œ‹๐‘Ÿ2โ„Ž = 1/3 ร— 22/7 ร— 7 โˆš7 ร— 7 โˆš7 ร— 21 cm3 = 22 ร— 7โˆš7 ร— 7 โˆš7 cm3 = 22 ร— 7 ร— 7 ร—(โˆš7)2 cm3 = 22 ร— 7 ร— 7 ร— 7 cm3 = 7546 cm3

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