In general, the area of a square is given by the formula below
[tex]\begin{gathered} A_{square}=l^2 \\ l\rightarrow\text{ side of the square} \end{gathered}[/tex]
Therefore, in our case,
[tex]\begin{gathered} l=2 \\ \Rightarrow \\ A=2^2=2*2=4 \end{gathered}[/tex]
Thus, the answer is 4 km^2
