To find the area of the shaded region, you find the area of the big circle and subtract it by the area of the small circle.
The larger circle's diameter is 36yd, which makes the radius 18yd
The area of a circle is:
[tex]A = \pi r^{2} = \pi (18)^{2} = 1017.8784 yd^{2}[/tex]
The smaller circle's diameter is 16 yards, r = 8 yards
[tex]A = \pi (8)^{2} = 201.0624 yd^{2}[/tex]
1017.8784 - 201.0624 = 816.816 yd²
