∵∠ABC的平分线BD与△ACB的外角∠ACE的平分线CD相交于点D,∴∠4= 1 2 ∠ACE,∠2= 1 2 ∠ABC,∵∠DCE是△BCD的外角,∴∠D=∠4-∠2,= 1 2 ∠ACE- 1 2 ∠ABC,= 1 2 (∠A+∠ABC)- 1 2 ∠ABC,= 1 2 ∠A+ 1 2 ∠ABC- 1 2 ∠ABC= 1 2 ∠A,∵∠A=50°,∴∠D=25°.