Question

the radius of a hemisphere balloon increases from 7cm to 14cm as air is being pumped into . find the ratio 's of the surface areas of the balloon in the to cases

Answer 1

Let Surface Area of Balloon with radius 7 cm=SA¹
SA¹= 4πr²
=4×22/7×7×7
=616 cm²

Let Surface Area of balloon with radius 14 cm=SA²
SA²=4πr²
=4×22/7×14×14
=2464 cm²

Ratio= 616:2464
= 1:4