Perimeter of rectangle : Perimeter of square = 10 : 7. Square side = 14 cm.

• Perimeter of square = 4 × 14 = 56 cm
• Perimeter of rectangle = \(\frac{10}{7}\) × 56 = 80 cm
• L + B = 80 ÷ 2 = 40 cm
• Given answer: L − B = 10 cm
• L = (40 + 10) ÷ 2 = 25 cm, B = (40 − 10) ÷ 2 = 15 cm
• Check: B : L = 15 : 25 = 3 : 5

The difference between length and breadth is 10 cm.
Check: P = 2(25 + 15) = 80. 80 : 56 = 10 : 7. ✓