It is given that ABCD is a parallelogram. AD || BC and AB || DC (Opposite sides of a parallelogram are parallel to each other)
Join point A to point C.
ΔAPC and ΔBPC are lying on the same base PC and between the same parallels PC and AB.
Therefore,
ar(ΔAPC)=ar(ΔBPC)...(1) In quadrilateral ACQD, AD = CQ AD || BC (Opposite sides of a parallelogram are parallel) CQ is a line segment which is obtained when line segment BC is produced. ∴AD||CQ We have, AC = DQ and AC|| DQ Hence, ACQD is a parallelogram.
Consider ΔDCQ and ΔACQ These are on the same base CQ and between the same parallels CQ and AD. Therefore, ar(ΔDCQ)=ar(ΔACQ) Then,
ar(ΔDCQ)−ar(ΔPQC)=ar(ΔACQ)−ar(ΔPQC) [Subtracting
Area(ΔPQC) from both sides]
Δar(ΔDPQ)=ar(ΔAPC)...(2) From equations (1) and(2), we obtain
ar(ΔBPC)=ar(ΔDPQ)