The area of a circle with radius r is given by::
[tex]A=\pi r^2[/tex]
For r = 5 miles, we have:
[tex]A\approx3.14\cdot5=15.7\text{ miles}^2[/tex]
Considering that P 635,000 people lives in this area, the population density d is given by:
[tex]d=\frac{P}{A}=\frac{635000}{15.7}=\approx40,445.86\text{ }\frac{people}{mile^2}[/tex]
