You have one square that is 11 m on a side. Its area is 112
You have four quarter circles which is equivalent to one whole circle with radius 5.5 m. Its area is 3.14 x 5.52
Figure up those two areas and subtract the circle from the square.
121 square meters – 94.985 square meters = 26.015 square meters, rounded is 26.02 square meters