Assuming the earth to be a sphere of radius 6370 km, how many square kilometres is area of the land, if three-fourth of the earth’s surface is covered by water?

Surface area of a spere = 4πr²

Given, earth is a sphere of radius 6370 km.

Surface area of earth = 4 × (22/7) × 6370²

⇒ Surface area of earth = 510109600 km²

Now, three-fourth of the earth’s surface is covered by water

Area covered by land = 1/4 × 510109600 = 127527400 km²