1. **State the problem:** We need to find the percentage of students in band at Deer Creek Middle School. 2. **Identify the given values:** Total students = 1249, Students in band = 521. 3. **Formula for percentage:** $$\text{Percentage} = \left(\frac{\text{Part}}{\text{Whole}}\right) \times 100$$ 4. **Apply the formula:** $$\text{Percentage} = \left(\frac{521}{1249}\right) \times 100$$ 5. **Calculate the fraction:** $$\frac{521}{1249} \approx 0.4179$$ 6. **Multiply by 100 to get percent:** $$0.4179 \times 100 = 41.79$$ 7. **Round to the nearest whole number:** $$\boxed{42\%}$$ **Answer:** Approximately 42% of the students are in band.