AOF40的精選

問題詳情：如圖，AB是⊙O的直徑，EF，EB是⊙O的弦，且EF=EB，EF與AB交於點C，連接OF，若∠AOF=40°，則∠F的度數是（   ）A．20°                       B．35°                       C．40...