题目

已知∠AOB=120°，射线OC在∠AOB的内部，且∠AOC=80°，若存在∠COD=3∠BOC，则∠AOD=___________. 答案：【答案】40°或160°【解析】解：∵∠AOB=120°，∠AOC=80°，∴∠BOC=∠AOB-∠AOC=120°-80°=40°,∵∠COD=3∠BOC,∴∠COD=3×40°=120°,如图，当OD在OB左侧时，∠AOD=∠COD-∠AOC=120°-80°=40°，当OD在OB右侧时，∠AOD=360°-∠AOC-∠COD=360°-80°-120°=160°，综上，∠AOD=40°或160°.She ________ go with us．She's at work．A.canB.can'tC.isD.isn't