The area of the parallelogram is the product of its base length and height, (12 ft)*(12 ft) = 144 ft^2.
The area of the cutout is the product of its base length and height, (6 ft)*(8 ft) = 48 ft^2.
The shaded area is the area of the parallelogram less the area of the cutout,
144 ft^2 -48 ft^2 = 96 ft^2.