In Δs AOQ and BOP, we have
∠OAQ = ∠OBP (Each equal to 90°)
∠AOQ = ∠POB (Vertically opp.∠s)
∴ By AA–similarity,
ΔAOQ ~ ΔBOP
⇒ \(\frac{AO}{BO}=\frac{OQ}{OP}=\frac{AQ}{BP}\)
⇒ \(\frac{AO}{BO}=\frac{AQ}{BP}\) ⇒ \(\frac{10}{6}=\frac{AQ}{9}⇒AQ=\frac{10\times9}{6} = 15 cm.\)