A square and a rectangular field with measurements as given in the figure have the same perimeter. Which field has a larger area?

Side of a square , s= 60 m 

length of a rectangular field, l = 80 m

Since, Perimeter of rectangular field = Perimeter of square field

Therefore, $2 (l + b) = 4\times Side$

 ⇒$2(80+b) = 4\times 60$

⇒$160+2b = 240$ 

⇒ $b = 40$

Hence, Breadth of the rectangle is 40 m. 

Now, Area of Square field $=sid{e}^2= {60}^2= 3600 m^2$ 

And, Area of Rectangular field =$length\times breadth =$$80\times 40 = 3200 m^2$

Hence, area of square field is larger.