Question

如图,BP,CP分别平分∠ABD,∠ACD,若∠A=60°,求∠P

Answer 1

∵∠ACD＝∠A+∠ABC,CP平分∠ACD

∴∠PCD＝∠ACD/2＝（∠A+∠ABC）/2

∵BP平分∠ABC

∴∠PBC＝∠ABC/2

∴∠PCD＝∠P+∠PBC＝∠P+∠ABC/2

∴∠P+∠ABC/2＝（∠A+∠ABC）/2

∴∠P＝∠A/2＝60°/2＝30°