Help me please I’m losted

Answer:
[tex]\frac{50}{3}[/tex]
Step-by-step explanation:
Similar shapes have corresponding sides that are proportional.
So 20 corresponds to x (big to small).
So 12 corresponds to 10 (big to small).
Your information is already lined up for you to setup your proportion:
[tex]\frac{20}{12}=\frac{x}{10}[/tex]
Cross multiply:
[tex]20(10)=12(x)[/tex]
Simplify both sides:
[tex]200=12x[/tex]
Divide both sides by 12:
[tex]\frac{200}{12}=x[/tex]
Simplify by dividing top and bottom by 4:
[tex]\frac{50}{3}=x[/tex]