Question

The sides of a rectangle Park is 4 is to 3 if the area of 1728 m square find the cost of fencing it at rupees 30 per metre

Answer 1

Let 4x and 3x be the dimension of the rectangular park 

According to the question - 

4x × 3x = 1728
12x^2=1728m^2
x^2=144
x=√144
x=12
L = 4x => 4 ×12 = 48 
B = 3x => 3 × 12 = 36 

Perimeter = 2( l+ b) 

= 2 ( 48+36) 
= 168

cost = rate × perimeter 
= 30 × 168

= ₹ 5040

Answer 2

Area of the field = ( 4x * 3x)m^2

=12x^2m^2

But it is given that area is 1728 m^2

12x^2 =1728

X^2 =(1728/12)= 144

X= 144=12

Length =(4×12) m = 48 m

Breadth =(3× 84)m = 36m

Perimeter of the field =2×(L+B)

=2 (48+36)m= (2×84) m =168m

Cost of fencing =rs (168×30)

Rs =5040