Find the area enclosed by the figure

The area of the greater rectangle:
[tex]A_G=56\cdot(17+18+21)=56\cdot56=3,136\ ft^2[/tex]
The area of the smaller rectangle:
[tex]A_S=26\cdot18=468\ ft^2[/tex]
The area of the figure:
[tex]A=A_G-A_S\to A=3,136-468=2,668\ ft^2[/tex]