如图,在△ABC中,∠ABC和∠ACB的外角平分线交于点O,且∠BOC=40°,则∠A=(  )A.10°B.70°C.100

2025-05-21 01:48:58
推荐回答(1个)
回答(1):

∠BOC=40°
∴∠OBC+∠OCB=140°
∴∠ABC+∠ACB=180°×2-140°×2=80°
∴∠A=180°-(∠ABC+∠ACB)=180°-80°=100°.
故选C.