A cylinder of radius 12cm contains water to a depth of 20cm. A spherical iron ball is dropped into the cylinder and thus the level of water is raised by 6.75 cm. Find the radius of the ball. `(u s epi=(22)/7)`

Explanation

Volume of water`=pi(12)^2h=144pihcm^3`

Volume=`pi(12)^2[h+6.75]`

`=(144pih+972pi)cm^3`

`V_f=V_w+V_s`

`144pih+972pi=144pih+4/3pir^3`

`r^3=3/4*972=729`

`r^3=9^3`

`r=9cm`.