Let the radius of the earth be r.
Then, diameter of the earth = 2r

 Diameter of the moon 

  Radius of the moon = 

Volume of the earth (v₁) = 
Volume of the moon (v₂)



 (volume of the earth)

Hence, the volume of the moon is  th fraction of the volume of the earth.

Diameter = 10.5 cm

 Radius (r) = 

  Amount of milk = 

                 

Density = 8.9 g per cm³
Mass of the ball = Volume x Density
= 38.808 x 8.9 = 345.39 g (approx.).