已知,AD = AC ,BE = BC ,可得：∠ADC = ∠ACD ,∠BEC = ∠BCE ,即有：∠EDC = ∠ACD = ∠ACE+∠ECD ,∠DEC = ∠BCE = ∠BCD+∠ECD ,∠ECD = 180°-(∠EDC+∠DEC)= 180°-(∠ACE+∠ECD+∠BCD+∠ECD)= 180°-(∠ACB+∠...