Answer: The radius of the circle is 40 ft.
Step-by-step explanation
• The square lawn area is 3200 ft².
The formula for the area of a square (A) is:
![A=s^2](https://img.qammunity.org/2023/formulas/mathematics/college/g5w0s4tc8dlfxhp0bptnbomr5cm8ow9lkl.png)
where s represents the side.
If we replace the area, we can find the side:
![s^2=3200](https://img.qammunity.org/2023/formulas/mathematics/college/ut258dgac6rd97yxnfjytf4yqh3bcim06d.png)
![√(s^2)=√(3200)](https://img.qammunity.org/2023/formulas/mathematics/college/53e60sjwx3ogsxcnoas74id07v8mcvlzlg.png)
![s=40√(2)](https://img.qammunity.org/2023/formulas/mathematics/college/bd5kskzrdssviheppjnazhbiwilpzc3lz6.png)
If the sprinkler is placed at the center of the lawn spraying water in a circular pattern that covers the lawn, the diameter ( d ) of the circle is equal to the diagonal of the square:
![d=√(s^2+s^2)](https://img.qammunity.org/2023/formulas/mathematics/college/8ax6c4vupfylkgi11c6vtml2xhkp7bszcu.png)
Replacing the values:
![d=√(3200+3200)](https://img.qammunity.org/2023/formulas/mathematics/college/rqopi7fyyazbgj3ufcci0w4p7vdt0oyc8h.png)
Simpifying:
![d=√(6400)](https://img.qammunity.org/2023/formulas/mathematics/college/74e31k0fcjzdabhtzgmjxk391tae543ldr.png)
![d=80ft](https://img.qammunity.org/2023/formulas/mathematics/college/eqm39f6rt1uexa8n7cfy4regzlkl0d5744.png)
However, as the radius ( r ) is half the diameter then:
![r=(d)/(2)](https://img.qammunity.org/2023/formulas/mathematics/high-school/lbj8f6aiw49vzkvm3ph9oaipc5fcjll3n9.png)
![r=(80)/(2)=40](https://img.qammunity.org/2023/formulas/mathematics/college/o2ydnd3rtge8ea81p7e2963doyr2kal1ex.png)
The radius is 40ft.