the shaded area is the area of the semicircle minus the area of the triangle. The area of of the semicircle is
pi(4Sq)/2=8pi
To calculate the area of the triangle we need to drop an altitude from C to the diameter and label that point d. we then have 2 congruent triangles CDB and COD
So OD=DB=2
Now we can solve for the altitude 4sq=2sq + xs
Xsq= 12 x = sq rt12 Area if triangle = (1/2)base x altitude = (1/2) (8)(sq rt 12)= 4sqrt 12
shaded area is 8pi - 4sqrt 12