In similarity statements, the order in which vertices are listed matters! From the similarity of [tex]\triangle PQR[/tex] and [tex]\triangle FGH,[/tex] we have [tex]\frac{PQ}{FG}=\frac{QR}{GH}.[/tex] Plugging in our known values gives us [tex]\frac{10.5}{7}=\frac{9}{n},[/tex] and solving, we have [tex]\boxed{n=6}.[/tex]
