In a △ABC, Let P and Q be points on AB and AC respectively such that PQ || BC. Prove that median AD bisects PQ.
Suppose the median AD intersects PQ at E.
Now, PQ || BC [Corresponding angles]
⇒∠APE=∠B and ∠AQE=∠C
So, in △′s APE and ABD, we have
∠APE=∠ABD and, ∠PAE=∠BAD [common]
∴△APE∼△ABD
△APQ∼△ABC
So, PEBD=PQBC
PEBD=PQ2BD
We get, PQ=2PE
Hence, proved.