重点难点易混易错点剖析等腰三角形是轴对称图形,等边对等角,“三线合一”等是其主要特性,在题目没有明确给出腰和底角的情况下,尤其要考虑周全,实施必要的分类讨论.在直角三角形中,30°角所对的直角边等于斜边的一半,斜边上的中线等于斜边的一半,以及勾股定理等都是我们处理相关问题的重要工具,解题时一定要注意定理的适用条件,厘清一般和特殊、性质与判定的联系与区别. Difficult points easy to mislead misunderstanding Analysis of isosceles triangle axisymmetric graphics, equilateral equilateral, “three-in-one ” and so is its main characteristic, the problem is not clearly given waist and bottom corner of the case, especially In the right triangle, the angle of 30 ° to the right-angle side is equal to half the hypotenuse, the hypotenuse of the middle line is equal to half of the hypotenuse, and the Pythagorean theorem are all we deal with Important tools of the problem, the problem must pay attention to the conditions of application of the theorem, to clarify the general and special, the nature and the relationship between the judge and the difference.