A triangle has a perimeter of 81 cm, and its sides are proportional to 4:3:2. What is the length of the longest side?

Explanation

Let the sides be 4x, 3x, and 2x. Their sum is 4x + 3x + 2x = 9x, which equals the perimeter 81 cm. Solving for x gives x = 9. The longest side is 4x = 4 × 9 = 36 cm.