1. **State the problem:** We want to find the population of San Diego given that it is about 85% of the population of Phoenix, which is 1.8 million people. 2. **Formula:** To find a percentage of a quantity, multiply the quantity by the percentage expressed as a decimal. 3. **Convert percentage to decimal:** 85% = \frac{85}{100} = 0.85 4. **Calculate population of San Diego:** $$\text{Population of San Diego} = 1.8 \times 0.85$$ 5. **Perform multiplication:** $$1.8 \times 0.85 = 1.53$$ 6. **Interpretation:** The population of San Diego is approximately 1.53 million people. 7. **Expressions that represent this approximation:** - $1.8 \times 0.85$ - $0.85 \times 1.8$ - $\frac{85}{100} \times 1.8$ - $1.8 \times \frac{85}{100}$ All these expressions correctly approximate the population of San Diego in millions.