Can someone please help me answer this?

Answer:
B
Step-by-step explanation:
If you don't understand some steps, comment it for me please.
1. Find diagonal.
d = 2r
d = 2(9)
d = 18
2. Find length of square.
each length of square = x
[tex]x : 18 = 1 : \sqrt{2}[/tex]
[tex]\frac{x}{18} = \frac{1}{\sqrt{2} }[/tex]
[tex]\sqrt{2}x = 18[/tex]
[tex]x = \frac{18}{\sqrt{2} } = 9\sqrt{2}[/tex]
3. Find area of circle and square.
Area for circle
[tex]A = \pi r^2[/tex]
[tex]A = \pi (9)^2[/tex]
[tex]A = 81\pi = 254.4690...[/tex]
Area for square
[tex]A = (length)^2[/tex]
[tex]A = (9\sqrt{2})^2[/tex]
[tex]A = 162[/tex]
4. Subtract area of circle to area of square.
254.4690... - 162 = 92.4690...
5. Find the shaded region.
92.4690... / 4 = 23.1172...
Rounded to the nearest hundredth = 23.12