Answer:
[tex]\large\boxed{\dfrac{50}{3}}[/tex]
Step-by-step explanation:
If the polygons are similar, then the corresponding sides are in proportion:
[tex]\dfrac{z}{10}=\dfrac{20}{12}[/tex] cross multiply
[tex]12z=(10)(20)[/tex]
[tex]12z=200[/tex] divide both sides by 12
[tex]z=\dfrac{200}{12}\\\\z=\dfrac{200:4}{12:4}\\\\z=\dfrac{50}{3}[/tex]
