Solution :
In triangle ABC,
Given, LM || CB
By Basic proportionality theorem, we have
\(AM\over AB\) = \(AL\over AC\) ……..(1)
In triangle ACD,
Given, LN || CD
By Basic proportionality theorem, we have
\(AL\over AC\) = \(AN\over AD\) ……..(2)
From (1) and (2), we obtain that
\(AM\over AB\) = \(AN\over AD\)