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Surface Areas and Volumes
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29/07/2021 10:53 am
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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.
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29/07/2021 10:54 am
Let r1 and r2 be the radii of spherical balloon and spherical balloon when air is pumped into it respectively.
r1 = 7cm
r2 = 14 cm
Required ratio = (initial surface area)/(Surface area after pumping air into balloon)
= 4r12/4r22
= (r1/r2)2
= (7/14)2 = (1/2)2 = 1/4
Therefore, the ratio between the surface areas is 1:4.