和圆的切线相关的试题,作为中考中档题,近几年出现较多,但因其条件不一,证法也不同,同学们不易把握.直线和圆相切的判定一般有三种方法.现总结如下. Questions related to round tangents have appeared in recent years as mid-term tests for middle school entrance examinations. However, due to different conditions and different certification methods, students are not easy to grasp. There are generally three methods for determining the tangency of straight lines and circles. Summarized as follows.