Question

assuming the earth to be a sphere of radius 6370km how many square kms is area of land if 3/4th of the earth surface is covered by water 

Answer 1

$radius \: of \: sphere = 6370km$
$area \: of \: sphere \: =4 \pi {r}^{2}$
$=4 \times \frac{22}{7} \times {6370}^{2}$
$= 510109600 {km}^{2}$
$if \frac{3}{4}area \: of \: earth \: is \: covered \: with \: water$
$then \: area \: of \: earth \: = \frac{3}{4} \times 510109600$
$= 382582200 {km}^{2}$