Answer:
[tex]\huge\boxed{z=3}[/tex]
Step-by-step explanation:
If two polygons are similar, then corresponding sides are in proportion.
The corresponding sides:
4 → x
y → 15
3 → w
2 → 6
z → 9
therefore:
[tex]\dfrac{z}{9}=\dfrac{2}{6}[/tex] cross multiply
[tex](z)(6)=(9)(2)[/tex]
[tex]6z=18[/tex] divide both sides by 6
[tex]z=3[/tex]
