Shadow 1+ shadow 2+ shadow 3+ shadow 4 = (1/4) π r? =25π? cm？

Shadow 1+ shadow 2 = shadow 2+ shadow 3 = (1/2) π (r/2)? =25π/2? cm？

So, Shadow 1+ Shadow 2= Shadow 3+ Shadow 4= Shadow 2+ Shadow 3= Shadow 1+ Shadow 4.

So, Shadow 1= Shadow 3, Shadow 2= Shadow 4.

Connect the intersection of two semicircles, the center of the semicircle and the center of the great circle into a square.

So the side length of a square is 5cm and the area is 25cm?

Half of a semicircle, the 90-degree sector area in a square is 25 π/4? cm？

So the area of shadow 2 is 2 times the sector minus the square = 25 (π/2- 1) cm?

So what? Shadow 2+ Shadow 4? =? 25(π-2)? cm？