Let us look at the relationship column-wise. | | |
In the first column:

$$\frac{18\times 12}{3}=\frac{216}{3}=72$$

In the third column:

$$\frac{32\times 16}{4}=\frac{512}{4}=128$$

Following the same logic for the second column, let the missing character be $x$:

$$\frac{24\times 14}{x}=112$$

$$\frac{336}{x}=112$$

$$x=\frac{336}{112}=3$$