The world's population passed 6.5 billion in 2006. Estimate the amount of land area required if each

Question:

The world's population passed 6.5 billion in 2006. Estimate the amount of land area required if each person were to stand in such a way as to be unable to touch another person. Compare this area to the land area of the United States, 3.5 million square miles, and to the land area of your home state (or country).