ANSWER
The correct answer is
21.5 square centimeters
EXPLANATION
The shaded area is the area of the square minus the area of the Circle.
Area of shaded region
[tex] = {l}^{2} - \pi \: {r}^{2} [/tex]
From the diagram,
[tex]l = 10cm[/tex]
and
[tex]r = \frac{l}{2} = \frac{10}{2} = 5cm[/tex]
This implies that,
Area of shaded region
[tex] = {10}^{2} - \pi \times {5}^{2} [/tex]
[tex] = 100 -25 \pi [/tex]
[tex] \approx21.5 {cm}^{2} [/tex]
