So △AEQ is similar to △CDQ.

△ Ape is similar to△△△ BPD.

So AE: DC = eq: dq

AE∶BD=PE∶PD

Because d is the midpoint of BC

So BD=DC

So AE: BD = EQ: DQ.

So PE: PD = eq: dq.

So pdeq = pedaq