Answer:
25
Step-by-step explanation:
As the triangles within the bigger triangle are similar, the sides are in proportion.
⇒ [tex]\frac{18}{30} = \frac{15}{w}[/tex]
⇒ [tex]\frac{3}{5} = \frac{15}{w}[/tex]
⇒ 3w = 75
⇒ w = 25
