Solution: ∵BC and AD are circles with radius 1/4. Area = (π 4 2)/4 = 4 π.

The area of a semicircle with a diameter of AB = [π (4/2) 2]/2 = 2π.

Square area = 4 2 =16

∫ Square area =2* 1/4 Circular area with BC as radius+Semicircular area with AB as diameter -3 Shadow area.

∴ Shadow area =(2*4π+2π- 16)/3

=( 10π- 16)/3