The perimeter of the shadow is the common sense learned in primary school, which is equivalent to the perimeter of the great circle outside, namely:

(4+4+4)x 3. 14 = 37.68 cm.

The area of the shadow is equivalent to the difference between the areas of a circle with a diameter of 8 cm and a circle with a diameter of 4 cm, namely:

4 2x3,14—(4/2) 2x3.14 = 37.68 square centimeters.