Given that the length of side of shaded area is 1 ft.
Making equal square of size of shaded area we have:
Horizontally number of shaded area are 12
Vertically number of shaded area are 11
So, the horizontal length of big rectangle is 12 ft.
The vertical length of big rectangle is 11 ft.
Area of big rectangle is 12*11
Area of given rectangle is 132 sq.ft.