Answer:
r = 5 km
Step-by-step explanation:
Given that,
The population in a circular region = 1.15 million
The population density of the region = 18075 people per kilometer
We need to find the radius of the region.
We can find the area of circular region i.e.
[tex]A=\dfrac{P}{d}\\\\A=\dfrac{1.15\times 10^6}{18075 }\\A=63.6\ km^2[/tex]
We know that the area of a circular region is given by :
[tex]A=\pi r^2\\\\\pi r^2=63.6\\\\r=\sqrt{\dfrac{63.6}{\pi}} \\\\r=4.49\ km[/tex]
or
r = 5 km
So, the radius of the region is equal to 5 km.