Let the missing number be "x". So, we can write,
[tex]\frac{8}{7}=\frac{x}{56}[/tex]We can easily solve for the unknown number (x) by cross multiplying and doing a bit of algebra.
The steps are shown below:
[tex]\begin{gathered} \frac{8}{7}=\frac{x}{56} \\ 7x=8\times56 \\ 7x=448 \\ x=\frac{448}{7} \\ x=64 \end{gathered}[/tex]