1. **Problem Statement:** A boy measures the length and breadth of a rectangle as 40 cm and 25 cm instead of the actual 45 cm and 30 cm respectively. We need to find the percentage error in: i) length ii) breadth iii) area of the rectangle. 2. **Percentage Error Formula:** Percentage error in a measurement = $$\frac{|\text{measured value} - \text{true value}|}{\text{true value}} \times 100$$ 3. **Calculate percentage error in length:** True length = 45 cm Measured length = 40 cm Percentage error = $$\frac{|40 - 45|}{45} \times 100 = \frac{5}{45} \times 100 = 11.11\%$$ 4. **Calculate percentage error in breadth:** True breadth = 30 cm Measured breadth = 25 cm Percentage error = $$\frac{|25 - 30|}{30} \times 100 = \frac{5}{30} \times 100 = 16.67\%$$ 5. **Calculate percentage error in area:** True area = length \times breadth = 45 \times 30 = 1350 \text{ cm}^2 Measured area = 40 \times 25 = 1000 \text{ cm}^2 Percentage error = $$\frac{|1000 - 1350|}{1350} \times 100 = \frac{350}{1350} \times 100 \approx 25.93\%$$ **Final answers:** i) Length percentage error = 11.11% ii) Breadth percentage error = 16.67% iii) Area percentage error = 25.93%