Find the length of the missing side please help

Step-by-step explanation:
7. Since they are similar triangles we have:
[tex] \frac{10}{8} = \frac{x}{12} \\ \\ x = 15[/tex]
So DF is 15
8. They are also similar. So:
[tex] \frac{14}{7} = \frac{x}{5} \\ x = 10[/tex]
So PR is 10