see the attached figure to better understand the problem
we know that
the area of the figure is the area of the square minus the areas marked with x
area of the square is equal to
[tex]A1=8*8=64\ ft^{2}[/tex]
the areas marked with x is equal to
[tex]A2=15\ ft^{2}[/tex]
so
the area of the figure is
[tex]A=A1-A2 \\ A=64-15=49\ ft^{2}[/tex]
therefore
the answer is
[tex]50\ ft^{2}[/tex]
