The rate of change of surface area of a sphere of radius r when the radius is increasing at the rate of 2cm/sec is proportional torea is

Explanation

Given `((dr)/dt)=2 (cm)/sec`

Surface area of sphere` S=4pir^2`

`((ds)/dt)=8pir((dr)/dt)`

=`((ds)/dt)=16pir`

Therefore, Rate of change of surface area proportional radius of sphere.