Question

Suppose there exists a planet with 3.1 billion inhabitants. The surface area of this planet is 490,784,119 km ^2. What is the surface area of the planet in mi^2? Round to the nearest million square miles.

Answer 1

190 milion square miles

Explanation:

The conversion factor between kilometer and mile is:

1 mile = 1.609 km

So, the conversion factor between the squared mile and the square kilometer is

`(1 mile)^2 = (1.609 km)^2 = 2.589 km^2`

So we can set up the following proportion to find the surface area in mi^2:

`1 mi^2 : 2.589 km^2 = x : 490,784,119 km ^2\\x=((1 mi^2)(490,784,119 km ^2))/(2.589 km^2)=189,565,129 mi^2`

Rounded to the nearest milion square miles, it is 190 milion square miles.