1. **State the problem:** We need to find the percent decrease in the population of a city from 2010 to 2020. 2. **Given data:** - Initial population in 2010: $455,000$ - Population in 2020: $405,000$ 3. **Formula for percent decrease:** $$\text{Percent Decrease} = \frac{\text{Original Value} - \text{New Value}}{\text{Original Value}} \times 100\%$$ 4. **Calculate the decrease:** $$455,000 - 405,000 = 50,000$$ 5. **Apply the formula:** $$\text{Percent Decrease} = \frac{50,000}{455,000} \times 100\%$$ 6. **Simplify the fraction:** $$\frac{50,000}{455,000} = \frac{\cancel{50,000}}{\cancel{455,000}} = \frac{50,000 \div 5,000}{455,000 \div 5,000} = \frac{10}{91}$$ 7. **Calculate the decimal:** $$\frac{10}{91} \approx 0.10989$$ 8. **Convert to percent:** $$0.10989 \times 100\% = 10.989\%$$ 9. **Round to the nearest tenth:** $$10.989\% \approx 11.0\%$$ **Final answer:** The percent decrease in population is **11.0%**.