Answer:
13 feet
Explanation:
Since it is a square and the perimeter is 36 feet, each side is equal to 36feet/4, 9 feet. To find the diagonal use the Pythagorean Theorem.
![a^(2)+b^(2)=c^(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/wps9fo3b4w26yqm8cwk32he0gvppf7n6m5.png)
![9^(2)+9^(2)=c^(2)](https://img.qammunity.org/2021/formulas/mathematics/college/qi9okwauu6i6rve9yx5ih7t3cmz6jyzjc7.png)
81+81=
![c^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/k35u7m6yuyioehiuxbng19npestgihit5x.png)
162=
![c^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/k35u7m6yuyioehiuxbng19npestgihit5x.png)
Square root both sides
c=12.728
To the nearest foot, it equals 13 feet.