Acricket ball is dropped into a cylindrical tank of water. the ball sinks to the bottom of the tank. the diameter of the cricket ball is 7.2 cm. the diameter of the cylindrical tank is 15 cm. calculate the increase in height of the water in the tank.

Volume of spherical ball = 4/3 22/7 r^3
which should be equal to raise in height of water 
    as displaced water volume = volume of our cricket ball.

22/7 * 7.5 (radius of cylindrical tank) ^2 * h (height) = 4/3 22/7 r^3

which equates to 
h = 4/3 * 3.6^3 / 7.5^2