To find the area of a square, you can use the formula:
\[ \text{Area} = \text{side} \times \text{side} \]
In this case, the side length of the square is 13 feet. Therefore:
\[ \text{Area} = 13 , \text{ft} \times 13 , \text{ft} = 169 , \text{ft}^2 \]
The correct response is:
169 ft.²