A solid metallic cylinder of radius 4 cm and height 20 cm is melted so as to make 8 identical small solid cylinders each of radius 2 cm. Find the height of the small cylinders.

Find the approximate volume and surface area of a sphere of radius 6 cm. (Use π = 227)

Ram has two spherical balls of radius 10.5 cm each and Meena has six spherical balls of radius 7 cm each. What is the total volume of the balls that Meena has?