so from other comments
circle inscribed in a square
squaer is 10 by 10
shaded area is inside square but not circle
so
area of square=side^2
area of circle=pir^2
d/2=r
10/2=5=r
area of square-area of circle=shaded
10^2=100
pi5^2= aprox 78.5398
100-78.5398=21.4602
shaded=21.4602 cm^2
