That area is the square is 25 x 25 = 625
The circle touches the square so the diameter of the circle is 25.
Area of the circle = pi x r ^2 where r is half the diameter.
Area of circle = 3.14 x 12.5^2 = 490.625
The area of the shaded region is the area of the square - area of the circle:
625 - 490.625 = 134.375 square feet.