Find the missing length in the image below

Let it be x
[tex]\\ \sf\longmapsto \dfrac{x}{10}=\dfrac{3}{6}[/tex]
[tex]\\ \sf\longmapsto 6x=10(3)[/tex]
[tex]\\ \sf\longmapsto 6x=30[/tex]
[tex]\\ \sf\longmapsto x=\dfrac{30}{6}[/tex]
[tex]\\ \sf\longmapsto x=5[/tex]