Last updated at May 29, 2018 by Teachoo

Transcript

Ex 13.4 , 7 The diameter of the moon is approximately one fourth of the diameter of the earth. Find the ratio of their surface areas. Let diameter of earth = x So, diameter of moon = ๐ฅ/4 Hence, Radius of earth = ๐ฅ/2 & Radius of moon = 1/2ร๐ฅ/4 = ๐ฅ/8 Ratio of their surface area = (๐๐ข๐๐๐๐๐ ๐๐๐๐ ๐๐ ๐๐๐๐)/(๐๐ข๐๐๐๐๐ ๐๐๐๐ ๐๐๐๐๐๐กโ) = (4๐(๐ ๐๐๐๐ข๐ ๐๐ ๐๐๐๐)^2)/(4๐(๐ ๐๐๐๐ข๐ ๐๐ ๐๐๐๐กโ)^2 ) = (๐ ๐๐๐๐ข๐ ๐๐ ๐๐๐๐)^2/(๐ ๐๐๐๐ข๐ ๐๐ ๐๐๐๐กโ)^2 = (๐ฅ/8)^2/(๐ฅ/2)^2 = (๐ฅ^2/8^2 )/(๐ฅ^2/2^2 ) = ๐ฅ^2/8^2 ร 2^2/๐ฅ^2 = ๐ฅ^2/64 ร 4/๐ฅ^2 = 1/16

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

Serial order wise

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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.