In the following three problems enter your answers with at least four digits.
You propose to build a space ship that allows the entire population of the United States (280 million) to leave the earth. Your plans allocate an average space of $1,000 (=10\times 10 \times 10)$ cubic feet to each person. Your space ship is going to have the shape of a sphere. The radius of your space ship is feet.
Hint: The volume of a sphere of radius $r$ equals $\frac{4}{3}\pi r^3$.