Question

The side of a rectangular park are in the ratio 4 : 3. If the area is 1728 m find the cost of fencing it at the rate of Rs . 2.50m

Answer 1

The ratio of the sides = 4 : 3 

Let the sides be 4x and 3x 

Area = 1728 

l × b = 1728 

4x × 3x = 1728 

12x² = 1728 

x² = \(\frac{12}{1728}\)

x² = 144 

x = √144 = 12m 

4x = 4 × 12=48m 

3x = 3x ×12 = 36m 

Perimeter =4x + 3x + 4x + 3x 

= 48 + 36 + 48 + 36 

= 168 m 

The cost of fencing 1 m is Rs 2.50 

The cost of fencing 168 m = 168 × 250 = Rs.420.