The diameter of a solid hemisphere is 42 cm. What is the cost (in ₹, rounded off to the nearest ₹) of painting the entire surface of the hemisphere at the rate of ₹1.80 per cm2? (Take π = 227)

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?