Respuesta :

[tex]\begin{gathered} \frac{x}{126}=\text{ }\frac{45}{63} \\ \frac{x}{126}\text{ = }\frac{5}{7} \\ 7x\text{ = 126 x 5} \\ 7x=630 \\ x=\frac{630}{7} \\ x=90 \end{gathered}[/tex]