How much surface of earth is covered by water ?

How much earth is surrounded by water ?

Rukhsar painted the outside of the cabinet of measure 1 m xx 2 m xx 1.5 m .How much surface area did she cover if she painted all except the bottom of the cainet?

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