We have to fill the blank to find an equivalent fraction:
[tex]\begin{gathered} \frac{x}{4}=\frac{12}{16} \\ x=\frac{12}{16}\cdot4 \\ x=12\cdot\frac{4}{16} \\ x=12\cdot\frac{1}{4} \\ x=\frac{12}{4} \\ x=3 \end{gathered}[/tex]Answer: fill the blank with 3.