If both triangles are similar the ratio of sides will be same
[tex]\\ \sf\longmapsto \frac{x}{24} = \frac{6}{12} \\ \\ \sf\longmapsto 12x = 6 \times 24 \\ \\ \sf\longmapsto 12x = 144 \\ \\ \sf\longmapsto x = \frac{144}{12} \\ \\ \sf\longmapsto x = 12[/tex]
