学校召开秋季运动会,小李同学被分派担任铅球比赛的裁判.体育老师告诉他测量成绩的方法是:将皮尺的零刻度端放在A点,拉紧皮尺使皮尺过圆心O点,OA与⊙O的交点B在皮尺上所对的刻度的示数就是该运动员的成绩(如图1).在担当裁判时,小李发现,用皮尺量运动员的成绩,皮尺的一端A是铅球 The school held a fall sports meeting. Xiao Li was assigned to serve as a referee for the shot put competition. The physical education teacher told him to measure the grade by placing the zero scale end of the tape measure at point A and tightening the tape to make the tape measure round O, OA and ⊙. The scale of O’s intersection point B on the tape measure is the athlete’s performance (see Figure 1). When acting as a referee, Li found that using a tape measure to measure the athlete’s performance, one end of the tape measure is shot