Solution:-
From the question it is given that, ABC is a triangle in which AB = AC.
P is a point on the side BC such that PM ⊥ AB and PN ⊥ AC.
We have to prove that, BM x NP = CN x MP
Consider the ∆ABC
AB = AC … [from the question]
∠B = ∠C … [angles opposite to equal sides]
Then, consider ∆BMP and ∆CNP
∠M = ∠N
Therefore, ∆BMP ~ ∆CNP
So, BM/CN = MP/NP
By cross multiplication we get,
BM x NP = CN x MP
Hence it is proved.