The three sides are 3, 4 and 5 units. The perimeter of 60 cm is split into 12 units.<br><br>[[model:questions/solutions/q4495.png]]<br><br>• Total units → 3 + 4 + 5 = 12<br>• 12 units → 60 cm<br>• $$\frac{1}{1}$$ unit → 60 ÷ 12 = 5 cm<br>• Shortest side → 3 × 5 = 15 cm<br>• Longest side → 5 × 5 = 25 cm<br>• Difference → 25 − 15 = 10 cm<br><br>The difference between the longest side and the shortest side is 10 cm.<br>Check: Middle side = 4 × 5 = 20 cm. Perimeter: 15 + 20 + 25 = 60 cm. ✓