The perimeter of a triangle is 36 cm and its sides are in the ratio 3 : 4 : 5. Find the area of the triangle.
Let sides are a, b and c, a = 3x, b = 4x, c = 5x
Perimeter = a + b + c
=> 36 = 3x + 4x + 5x
=> x = 3
a = 9 cm, b = 12 cm and c = 15 cm
