In Fig. 14.99, ABCD is a parallelogram in which P is the mid-point of DC and Q is a point on AC such that CQ= AC. If PQ produced meets BC at R, Prove that R is a mid-point of BC.
Given,
Join B and D suppose AC and BD cut at D
Then, OC =
Now, CQ =
= CQ = =
In ∆DCO, P & Q are midpoints of DC & OC
∴ PQ
Also in ∆COB , Q is mid point of OC and QR││OB
∴ R is mid point of BC