Given ABCD is a parallelogram and AP=CQ
To show AC and PQ bisect each other.Proof in ΔAMP and ΔMCQ [alternate interior angles]
AP = CQ [ given]
And ∠APM=∠CQM [alternate interior angles]
∴ΔAMP≅ΔCMQ [ By ASA congruence rule]
⇒AM=CM [ By CPCT rule]
And PM = MQ [ By CPTC rule]
Hence, AC and PQ bisect each other.