we have that
the area of the shaded region is equal to the area of rectangle minus the area of the circle
step 1
Find the area of the circle
A=pi(r^2)
we have
r=4 units
substitute
A=pi(4^2)
A=16pi unit2
step 2
Find the area of rectangle
A=b*h
we have
h=2(4)=8 units
b=9+4=13 units
substitute
A=13(8)
A=104 unit2
therefore
the area of the shaded region is
A=(104-16pi) unit2