Shaded area = 21.46
Explanation:
First find area of square,
Area = length × width
A = 20 × 20
A = 400 cm^2
Secondly, find area of circle
Area of circle = (π)r^2
A = (π)10^2
A = 100 π
Thirdly, find the area outside of the circle
Area of square - Area of circle
400cm^2 - 100π
= 85.84
lastly divide the answer by 4 to find the shaded area
85.84 ÷ 4
= 21.46