In the adjoining figure, ABCD is a parallelogram in which AB is produced to E so that BE = AB. Prove that ED bisects BC.
Solution : In △ODCand△OEB , we have:
DC = BE
∴DC=AB
∠COD=∠BOE (Vertically opposite angles)
∠OCD=∠OBE (Alternate interior angles)
△ODC≅△OEB
⇒ OC = OB
(Cpctc )
We know that BC = OC + OB.
∴EDbisectsBC