Last updated at May 29, 2018 by Teachoo

Transcript

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 ๐๐2โ 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 = โ("7(49)" ) r = โ("7(7)2" ) r = 7โ7cm So, Volume of the come = 1/3 ๐๐2โ = 1/3 ร 22/7 ร 7 โ7 ร 7 โ7 ร 21 cm3 = 22 ร 7โ7 ร 7 โ7 cm3 = 22 ร 7 ร 7 ร(โ7)2 cm3 = 22 ร 7 ร 7 ร 7 cm3 = 7546 cm3

Examples

Chapter 13 Class 9 Surface Areas and Volumes (Term 2)

Serial order wise

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.