Step by step
The question
Question: find the population density when the population is 45,000 people and the area is 15 km².
Population 45,000 people, area 15 km². Find the population density.
1 Write the rule
The rule: population density is the population divided by the area.
population density = populationarea
Population density tells us how many people live on 1 km².
So its unit is people per km².
population density = the people on 1 km²
unit: people ÷ km² → people/km²
2 Put the numbers in
The population is 45,000.
The area is 15.
d = 45,00015
3 Work it out
Careful!
The population goes on the top.
The unit, people/km², shows it: people on the top.
Careful: not 1545,000 ✗
45,000 divided by 15 is 3000.
population density = 3000 people/km²
So the population density is 3000 people/km².
4 Check
Let's check.
3000 in each km², for 15 km²: 3000 times 15 is 45,000.
That is the population.
So the answer is right!
3000 people in each km²: 3000 × 15 = 45,000 people
Let's look back.
First: write the rule.
Then: put the numbers in.
Then: work it out.
Last: check.
Answer
population density = 3000 people/km²