When a wire is bent into the shape of a square, the area of the square is 81 cm2. If the same wire is bent into a semi-circular shape, what will be the area of the semicircle? [Take π = 22/7]

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?