As follows:

The area of each ring is π (5 2-4 2) = 9 π.

So the area of the five rings is: 5*9π=45π.

Therefore, the sum of quadrilaterals with small bends is: 45π- 122.5= 18.8.

As shown in the figure, a quadrilateral with eight small curved sides,

So each area: 18.8/8=2.35.