Given: ABCD is a parallelogram in which BD is diagonal and AP and CQ are drawn perpendiculars to BD from A and C respectively.
To prove: AP = CQ
Proof: Since diagonal of a parallelogram y divides its into two triangles equal in area.
∴ ar (∆ABD) = ar (∆BDC)
⇒ \(\frac { 1 }{ 2 }\) x BD x AP = \(\frac { 1 }{ 2 }\) x BD x QC
⇒ AP = QC
Hence proved.