Question 456578
The total surface area of Earth is about 1.97 × 10^8 square miles.
 The surface area of land on Earth is about 5.73 × 10^7 square miles.
:
{{{(5.73(10^7))/(1.97(10^8))}}}
we can also write it
{{{(5.73(10^7))/(19.7(10^7))}}}
Cancel the 10^7
5.73:19.7 is the ratio of land to total surface area