1. **Problem statement:** Find the percent error for Sam's foot measurement. 2. **Formula:** Percent error is calculated as $$\text{Percent Error} = \left| \frac{\text{Estimated Value} - \text{Actual Value}}{\text{Actual Value}} \right| \times 100$$ 3. **Apply values:** Estimated = 11 inches, Actual = 11.5 inches. $$\text{Percent Error} = \left| \frac{11 - 11.5}{11.5} \right| \times 100$$ 4. **Calculate numerator:** $$11 - 11.5 = -0.5$$ 5. **Substitute:** $$\left| \frac{-0.5}{11.5} \right| \times 100 = \frac{0.5}{11.5} \times 100$$ 6. **Simplify fraction:** $$\frac{0.5}{11.5} = \frac{\cancel{0.5}}{\cancel{11.5}} = 0.043478...$$ 7. **Multiply by 100:** $$0.043478... \times 100 = 4.3478...$$ 8. **Round to nearest tenth:** $$4.3$$ **Final answer:** The percent error is 4.3