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


Transcript

Ex 11.2 , 4 The radius of a spherical balloon increases from 7 cm to 14 cm as air is being pumped into it. Find the ratio of surface areas of the balloon in the two cases. Let r1 be the radius of smaller balloon = 7 cm and r2 be the radius of larger balloon = 14 cm Surface Area of sphere = 4 r2 Ratio of their surface areas = ( )/( ) = 4 12/4 22 = 12/ 22 = 7^2/ 14 ^2 = (7 7)/(14 14) = 1/4 Thus , the required ratio of their surface areas = 1 : 4

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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.