The breadth of rectangular field is two-thirds of its length. If its area is 864 m², then find the cost  of fencing it all around at ₹15/m.

₹1,800

We know that,

Area of rectangle = Length × Breadth 

perimeter of rectangle = 2 × (Length + breadth) 

Let the length = 3m  and

the breadth = 2m 

According to the question 

Area of rectangle = 864 

3m × 2m = 864 

= 6m² = 864 

= m² = 144 

= m = 12 

Length = 3m = 36 m 

Breadth = 2m = 24 m 

Perimeter of the rectangle = 2 × 60 = 120 m 

Total cost of fencing = 120 × 15  = 1800 rupees