A cylinder of base radius 35 cm and height 40 cm is bisected along its height to get two identical semi-cylinders. By what percent will the total surface area increase?

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?