Answer:
[tex]A=4r^{2}-r^{2}\pi[/tex]
Step-by-step explanation:
1. To calculate the area of the grass you must substract the area of the square and the area of the circle.
2. The area of the square is:
[tex]A1=L^2[/tex]
Where [tex]L[/tex] is one side of the square.
3. You have that:
[tex]L=2r[/tex]
4. Therefore:
[tex]A1=(2r)^{2} =4r^{2}[/tex]
5. The area of the circle is:
[tex]A2=r^{2}\pi[/tex]
6. The are of the grass is:
[tex]A=4r^{2}-r^{2}\pi[/tex]
