The sides of a rectangular park are in the ratio 4:3. If its area is 1

1.	The sides of a rectangular park are in the ratio 4:3. If its area is 1728 m2, find the cost of fencing it at ₹ 30 per meter.
Answer» Let the length of the field be 4x m Then, its breadth = 3x ∴area of the rectangular park = ((4x) × (3x)) = 12x²m² But, area = 1728m² (from the question) ∴12x²= 1728 = x² = 1728/12 = x² = 144 = x = √144 = x = 12 ∴length = (4 × 12) = 48m, breadth = 3 × 12 = 36m ∴perimeter of the field = 2(l + b) units = 2 (48 + 36) = 2 (84) = 168 m ∴the cost of fencing = ₹ (168 × 30) = ₹ 5040

The sides of a rectangular park are in the ratio 4:3. If its area is 1728 m2, find the cost of fencing it at ₹ 30 per meter.

Answer»

Let the length of the field be 4x m

Then, its breadth = 3x

∴area of the rectangular park = ((4x) × (3x)) = 12x²m²

But, area = 1728m² (from the question)

∴12x²= 1728

= x² = 1728/12

= x² = 144

= x = √144

= x = 12

∴length = (4 × 12) = 48m, breadth = 3 × 12 = 36m

∴perimeter of the field = 2(l + b) units

= 2 (48 + 36)

= 2 (84)

= 168 m

∴the cost of fencing = ₹ (168 × 30)

= ₹ 5040