In order to calculate the area of half a circle, we can use the formula below:
[tex]A=\frac{\pi r^2}{2}[/tex]
If the radius is 5 miles, the area is:
[tex]A=\frac{3.14\cdot5^2}{2}=39.25\text{ mi^^b2}[/tex]
Now, to find the population density, let's divide the population by the area:
[tex]d=\frac{P}{A}=\frac{550}{39.25}=14[/tex]
Therefore the density is 14 manatees per square mile.
