The city of Phoenix, Arizona has a population of 1,445,632 people and an area of 450 square miles. What is the population density of Phoenix? (To calculate population density you divide the number of people in a given place by the area of the land they live in.)

To calculate the population density of Phoenix, you divide the population by the area:

Population density = Population / Area

Using the given numbers:

Population = 1,445,632 people
Area = 450 square miles

Population density = 1,445,632 people / 450 square miles = 3,210.29 people per square mile (approximately).

Thus, the population density of Phoenix is about 3,210 people per square mile.

2. How did you arrive at this solution?

To arrive at the solution for the population density of Phoenix, I followed these steps:

1. **Understanding the Formula**: The formula for population density is:
\[
\text{Population Density} = \frac{\text{Population}}{\text{Area}}
\]
This means you take the total number of people living in an area and divide it by the size of that area.

2. **Gathering Information**: I extracted the relevant data provided:
- **Population**: 1,445,632 people
- **Area**: 450 square miles

3. **Applying the Formula**: I substituted the provided figures into the population density formula:
\[
\text{Population Density} = \frac{1,445,632 \text{ people}}{450 \text{ square miles}}
\]

4. **Performing the Calculation**: I divided 1,445,632 by 450 to get:
\[
\text{Population Density} \approx 3,210.29 \text{ people per square mile}
\]

5. **Rounding (if necessary)**: The population density is commonly rounded to a reasonable figure, so it can be stated as approximately 3,210 people per square mile for easier comprehension.

This straightforward approach allowed me to calculate the population density accurately.

3. How can this information about Phoenix be used to solve a policy problem such as transportation concerns or disease spread? write 3-4 sentences

(original and like a 9th grader wrote it)

Knowing the population density of Phoenix can help city planners and policymakers address transportation concerns. For example, with a population density of about 3,210 people per square mile, certain areas might have more traffic because more people live close together. This information can guide decisions on where to build new roads or public transport systems to better serve crowded neighborhoods. Additionally, high population density can also raise concerns about disease spread, since more people in close quarters can make it easier for illnesses to pass between individuals. Understanding where the most people live can help health officials plan vaccination campaigns or emergency responses more effectively.

Phoenix's population density of 3,210 people per square mile can guide city planners and policymakers in addressing transportation, disease spread, and health concerns. This information can guide decisions on road construction, public transport systems, and vaccination campaigns, ultimately improving city services.

1. How much did Japan’s population decline between 2012 and 2021?

Japan's population has been experiencing a decline in recent years. According to data from the World Bank and other statistical sources, Japan's estimated population was approximately 127.8 million in 2012 and around 125.5 million in 2021.

To find the population decline between 2012 and 2021:

1. **Population in 2012**: 127.8 million
2. **Population in 2021**: 125.5 million

**Population decline** = Population in 2012 - Population in 2021
**Population decline** = 127.8 million - 125.5 million = 2.3 million

Thus, Japan's population declined by approximately 2.3 million people between 2012 and 2021.

2. How did you arrive at this solution

To arrive at the solution regarding Japan's population decline between 2012 and 2021, I followed these steps:

1. **Identifying the Population Figures**: I referred to reliable sources for Japan’s population data. According to estimates:
- In 2012, Japan's population was approximately 127.8 million.
- In 2021, it was approximately 125.5 million.

2. **Setting Up the Calculation**: The goal was to determine how much the population decreased over this time period. To do that, I planned to subtract the population in 2021 from the population in 2012.

3. **Performing the Subtraction**: I calculated the difference:
\[
\text{Population decline} = \text{Population in 2012} - \text{Population in 2021}
\]
\[
\text{Population decline} = 127.8 \text{ million} - 125.5 \text{ million} = 2.3 \text{ million}
\]

4. **Interpreting the Result**: The result indicated that Japan's population had declined by approximately 2.3 million people over the nine-year period.

This methodical approach allowed me to arrive at an accurate understanding of Japan’s population decline during that timeframe.

3. How can the new information about Japan be used to make policy decisions in areas such as immigration?

The decline in Japan's population can significantly influence policy decisions regarding immigration. With fewer people in the workforce, the government might consider relaxing immigration policies to attract skilled workers from other countries, helping to fill labor shortages in various industries. Additionally, a decreasing population may lead to weakened economic growth, so encouraging immigrants could help sustain local economies. Policymakers can also focus on creating supportive environments for newcomers, such as providing language training and integration programs, which would not only help immigrants adapt but also enrich Japanese society and culture.