If the side length of a square garden is $2,800\text{meters}$, how much fencing is needed to enclose it?

The length of fencing required to enclose a square garden is equal to the perimeter of the square.
Given:

$$\text{Side of the square garden }(a)=2,800\text{meters}$$

The formula for the perimeter of a square is:

$$\text{Perimeter}=4\times a$$

$$\text{Perimeter}=4\times 2,800=11,200\text{meters}$$

Therefore, $11,200\text{meters}$ of fencing is needed.