答：∠BPC=½∠A,理由如下：根据题意设∠ABP=∠PBC=y,∠ACP=∠PCE=y∵∠ACE是△ABC的外角 ∴∠A+∠ABC=∠ACE, 即∠A+2y=2x ∴∠A=2x-2y=2(x-y)∵∠PCE是△PBC的外角 ∴∠P+∠PBC=∠PCE,&nbs...