Hii,
Given: ABCD is a trapezium with AB || CD
L is the mid point of BC and PQ || AD
Now, In ∆CLQ and ∆BLP
∠LCQ = ∠LBP (∵ AB || CDQ and BC is the transversal so, alternate interior opposite angles)
CL = BL (∵ L is the mid point of BC)
∠CLQ = ∠BLP (Vertically opposite angles)
So ∆CLQ ≅ ∆BLP ( by ASA congruency criteria)
⇒ Area (∆CLQ) = Area (∆BLP)
⇒ Area (ABCLP) + Area (∆CLQ) = Area (ADCLP) + Area (∆BLP)
Hence Area (APQD) = Area (ABCD)
Regards