Slide13.JPG

Slide14.JPG

 

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class


Transcript

Ex 11.2 , 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 = 𝑥/4 Hence, Radius of earth = 𝑥/2 & Radius of moon = 1/2×𝑥/4 = 𝑥/8 Ratio of their surface area = (𝑆𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑚𝑜𝑜𝑛)/(𝑆𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑜𝑓𝑒𝑎𝑟𝑡ℎ) = (4𝜋(𝑅𝑎𝑑𝑖𝑢𝑠 𝑜𝑓 𝑚𝑜𝑜𝑛)^2)/(4𝜋(𝑅𝑎𝑑𝑖𝑢𝑠 𝑜𝑓 𝑒𝑎𝑟𝑡ℎ)^2 ) = (𝑅𝑎𝑑𝑖𝑢𝑠 𝑜𝑓 𝑚𝑜𝑜𝑛)^2/(𝑅𝑎𝑑𝑖𝑢𝑠 𝑜𝑓 𝑒𝑎𝑟𝑡ℎ)^2 = (𝑥/8)^2/(𝑥/2)^2 = (𝑥^2/8^2 )/(𝑥^2/2^2 ) = 𝑥^2/8^2 × 2^2/𝑥^2 = 𝑥^2/64 × 4/𝑥^2 = 1/16

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.