In the figure, PQRS is a parallelogram with PQ = 16 cm and QR = 10 cm, L is a point on PR such that RL : LP = 2 : 3. QL produced meets RS at M and PS produced at N. Find the lengths of PN and RM.

In △RLQ and △PLN,

⇒ ∠RLQ = ∠PLN [Vertically opposite angles are equal]

⇒ ∠LRQ = ∠LPN [Alternate angles are equal]

∴ △RLQ ~ △PLN [By AA]

Since, corresponding sides of similar triangles are proportional we have :

$\Rightarrow \dfrac{RL}{LP} = \dfrac{RQ}{PN} \\[1em] \Rightarrow \dfrac{2}{3} = \dfrac{10}{PN} \\[1em] \Rightarrow PN = \dfrac{30}{2} = 15 \text{ cm}.$

In △RLM and △PLQ,

⇒ ∠RLM = ∠PLQ [Vertically opposite angles are equal]

⇒ ∠LRM = ∠LPQ [Alternate angles are equal]

∴ △RLM ~ △PLQ [By AA]

Since, corresponding sides of similar triangles are proportional we have :

$\Rightarrow \dfrac{RM}{PQ} = \dfrac{RL}{LP} \\[1em] \Rightarrow \dfrac{RM}{16} = \dfrac{2}{3} \\[1em] \Rightarrow RM = \dfrac{32}{3} = 10\dfrac{2}{3} \text{ cm}.$

Hence, PN = 15 cm and RM = $10 \dfrac{2}{3}$ cm.