P and Q are points on opposite sides AD and BC of a parallelogram ABCD such that PQ passes through the point of intersection O of its diagonals AC and BD. Then, point O ___.
bisects PQ
Given: ABCD is a parallelogram whose diagonals bisect each other at O.
In ΔODP and ΔOBQ,
∠BOQ=∠POD [Vertically opposite angles]
∠OBQ=∠ODP [atternate interior angles]
and OB = OD [given]
∴ΔODP≅ΔOBQ [by ASA congruence rule]
∴OP=OQ [CPCT]
So, PQ is bisected at O, or O bisects PQ.