The radius of a sphere shrinks from 10 to 9.8 cm. Find approximately the decrease in its volume.

Explanation

Volume of a sphere, `V = 4/3pir^3`

`:. (dV)/(dr) = 4/3pi(3r^2)`

`=> (dV)/(dr) = 4pir^2`

Here, `r = 10cm, dr = 9.8-10 = -0.2cm`

`:. (dV)/(-0.2) = 4pi(10)^2`

`=>dV = 400pi**(-0.2) = -80pi`.

So, decrease in volume of the sphere is `80pi cm^3`.