Question

The radius of a spherical balloon increases from 3 cm to 6 cm when air is being pumped into it. Then, the percentage increase in the surface area of the balloon is
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Answer 1

Step-by-step explanation:

Given radius r

1

=7 cm

r

2

=14 cm

Initial surface area (r

1

=7)=4πr

2

=4×

7

22

×7×7

=616 cm

2

Surface area (r

2

=14)=4πr

2

=4×

7

22

×14×14

=2464 cm

2

Ratio of surface area =

2464

616

=

4

1