Four cows are tied at the 4 corners (one at each corner) of a rectangular field of length 30 m and width 20 m. The length of each rope is 7 m. What is the area of the field that the cows CANNOT graze? (Use 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?