10. Find the ratio of surface area of the balloons

The radius of a spherical balloon increases from 18 \(cm\) to 27 \(cm\) as air being pumped into it. Find the ratio of the surface area of the balloons in the two cases.

 

 

The ratio of the surface area of the balloons \(=\) $i:i$

 

[Note: Enter only simplified ratio]