Please help! Explanation please!

Answer:
11 meters.
Step-by-step explanation:
The important thing to note here is that the backyard is a square. Since it's a square, all of its sides all equivalent in length. Thus, let's find the length of the sides. To do this, we use the area formula.
The formula for the area of a square is:
[tex]A=n^2[/tex]
Where n is a side. Since we know the area already, we can find n. Find n:
[tex]121=n^2\\n=11[/tex]
Since every side in a square are equivalent, all sides are 11 meters in length.
Therefore, each section of the fence should be 11 meters long.