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Answer :

Given :

Radius (r) of spherical balloon = 7 cm

Radius (R) of spherical balloon, when air is pumped into it = 14 cm

= \(\frac{Initial surface area}{Surface area after pumping air into balloon}\)

= \([\frac{4 × {\pi} × {r}^2}{4 × {\pi} × {R}^2}]\) \(= (\frac{r}{R})^2\)

= \((\frac{7}{14})^2 = \frac{1}{4}\)

Therefore, the ratio between the surface areas in these two cases is 1 : 4.

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