## Population Density

Population density is the number of people per unit of area, usually expressed as people per square kilometer (per km2) or people per square mile (per mi2). To calculate population density, divide the number of people in an area by the size of the area.
For example, a city has 10,000 people, and an area of 10 square miles. To calculate the density, do the following:
```people  = 10,000
area    = 10 square miles
density = 10,000 ÷ 10 square miles = 1,000 per mi2
```
Population density is the measure of how crowded an area is. In the USA, the average population density for a city is 4,300 per mi2. The USA as a whole has a population density of 91 per mi2. The average city has a much higher density than the entire country because cities are much more compact with less empty land.

### Exercise 1 of 6

Sacramento has 530,000 people, and an area of 100 square miles. How many people per square mile is the density?

### Exercise 2 of 6

New York City is the most dense city in the USA, excluding tiny cities that surround New York City. It has 8,325,000 people, and an area of 300 square miles. How many times more dense is New York City than the average city in the USA? Round to the nearest whole number.

### Exercise 3 of 6

Manila in the Philippines is the most dense city in the world. It has 1,840,000 people, and an area of 16 square miles. How many times more dense is Manila than the average city in the USA?

### Exercise 4 of 6

Bangladesh is the most dense country in the world, excluding city-states like Monaco and Singapore. It has 172,952,000 people, and an area of 52,000 square miles. How many times more dense is Bangladesh than the USA?

### Exercise 5 of 6

Mongolia is the least dense country in the world. It has 3,171,000 people, and an area of 604,000 square miles. How many times more dense is the USA than Mongolia?

### Exercise 6 of 6

Greenland is the least dense territory in the world. It has 58,520 people, and an area of 836,000 square miles. How many times more dense is the USA than Greenland?