r^2:2π/π=2
R= root number 2
Circumference: 2π* root number 2
Square:
Side length: root sign (2*π)
Perimeter: 2* root π * root 2
The circumference of an obvious circle is larger (because π >; Radical π)
The enlightenment is that the circumference of a circle and a square circle with the same area is large.