The total human population of the earth is about 6.2 × 10⁹.

a. If each person has the room of a prison cell (50 sq ft), and if there are about 2.8 × 10⁷ sq ft in a square mile, how many people could fit into a square mile?

b. How many square miles would be required to accommodate the entire human population of the earth?

c. If the total land area of the earth is about 5.2 × 10⁷ sq mi, and if all the land area were divided equally, how many acres of land would each person be allocated (1 sq mi = 640 acres)?