BO、 OC分别平分角 ABC和角 ACB ,（1）若角A=60度,求角O (2)若角A=100度、120度,角O又是多少?

(1)
∠A=60°
∠ABC+∠ACB ＝120°
BO、 OC分别平分∠ABC和∠ACB
∠OBC＋∠OCB = 60°
∠O = 120°
(2)
当∠A=100°
∠O = 180°- (180°-100°)÷2 = 140°
当∠A=120°
∠O = 180°- (180°-120°)÷2 = 150°