Answer
(25$\pi$ - 48)$ft^{2}$
Work Step by Step
In the circle diameter of the circle = diagonal of the rectangle
By pythagoras theorem
$diagonal^{2}$ = $6^{2}$ + $8^{2}$
$diagonal^{2}$ = 36 + 64
diagonal = $\sqrt 100 $ = 10 ft
Therefore the diameter of the circle = 10 ft
Area of the circle = $\pi r^{2}$
= $\pi (5)^{2}$ = 25 $\pi ft^{2}$
Area of rectangle = 6 * 8= 48 $ft^{2}$
Therefore the shaded area = (25$\pi$ - 48)$ft^{2}$