如图,AB为⊙O的直径,点C,D在⊙O上.若∠AOD=30°,则∠BCD等于( )A.75° ... 问题详情:如图,AB为⊙O的直径,点C,D在⊙O上.若∠AOD=30°,则∠BCD等于( )A.75° B.95° C.100° ...