The radius of a spherical balloon increases from 3.5 cm to 4.2 cm as air is being pumped into it, find the ratio of surface areas of the balloon in the two cases.

Asked by Topperlearning User | 18th Oct, 2017, 03:20: PM

Expert Answer:

Case I

When radius (R) = 3.5 cm

Surface area (S1) = begin mathsize 12px style 4 πR squared space equals space 4 cross times 22 over 7 cross times 3.5 cross times 3.5 space equals space 154 space cm squared end style

Case II: when radius (r) = 4.2 cm

Surface area (S2) = begin mathsize 12px style 4 πr squared space equals space 4 cross times 22 over 7 cross times 4.2 cross times 4.2 space equals space 221.76 space cm squared end style

 

Therefore, S1: S2 =25:36

 

Answered by  | 18th Oct, 2017, 05:20: PM

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