假设∠DAP=∠PAB=∠1,∠DMP=∠3,∠PNB=∠4,∠DCP=∠PCB=∠2
∠3=∠1+∠40=∠2+∠P
∠4=∠2+36=∠1+∠P
∠4-36+∠P=∠1+∠40
∠1+∠P-36+∠P=∠1+40
2∠P=76
∠P=38度
解:∠P=180°-∠DAO-∠BCD-∠AOD
=180°-1/2∠A-1/2∠C-(180°-∠D-∠A)
=1/2(∠A-∠C)+∠D
=1/2(∠B-∠D)+∠D
=1/2(∠B+∠D)
=38°