In Δ ABC, the bisector of ∠B meets AC at D. A line PQ || AC meets AB, BC and BD at P, Q and R respectively.
Show that PR × BQ = QR × BP.
In tringle BRQ and triangle BRP,
angle B is an common angle....1
angle R is also an common angle.......2
therefore,triangle BRQ is proportion to triangle BRP (AA congruence)
therefore,
BQ/BP=QR/RP
PR*BQ=QR*BP
Hence Proved..