The area of the square is 16 square inches.
The area of a square is calculated by multiplying a side by itself.
In this case, the side S is replaced by 4 in, then:
[tex]\begin{gathered} \begin{cases}A=S\cdot S \\ S=4in\end{cases} \\ A=4in\cdot4in=16in^2 \end{gathered}[/tex]