∵
∴
∵四边形ABCD为正方形
∴AB=AD,∠BAD=90°
∵AP=AD,∠PAD=40°
∴∠BAP=∠BAD+∠PAD=130°,AP=AB
∵∠PAD+∠ADP+∠APD=180°
∴∠APD=70°
∵∠PAB+∠APB+∠ABP=180°
∴∠APB=25°
∴∠BPD=∠APD-∠APB=45°
∵
∴
∵四边形ABCD为正方形
∴AB=AD,∠BAD=90°
∵AP=AD,∠PAD=40°
∴∠BAP=∠BAD+∠PAD=130°,AP=AB
∵∠PAD+∠ADP+∠APD=180°
∴∠APD=70°
∵∠PAB+∠APB+∠ABP=180°
∴∠APB=25°
∴∠BPD=∠APD-∠APB=45°