**Solution:**

Length = l

Breadth = b

**Perimeter = 2(L+b) = 80 **

=> l+b = 40 .......... (eq 1)

**Area = lb = 400** ........... (eq 2)

=> (l+b)^{2 }= (l-b)^{2} + 4lb

=> 40^{2} = (l-b)^{2 }+ 4 x 400 [From eqn 1 & 2)

=> 1600 = (l-b)^{2} + 1600

=> l-b = 0 .................... (eq 3)

L+b = 40

L-b = 0

2L = 40 => L = 20.

If L=20, then B=20

So, yes ! **We can construct a rectangular park of this length which is a square. Square is a Rectangle. **