等腰三角形的性质定理和判定定理在几何证明中应用十分广泛, 　但许多题的图形中并没有显示现成的等腰三角形.现介绍构造等腰三角形的几种方法,供读者参考. 一、在题图中,如果出现有一个公共端点的相等线段,那么必有隐藏的等腰三角形可利用,把非公共端点的两点连结起来 The properties theorems and decision theorems of isosceles triangles are widely used in geometrical proofs, but the isosceles triangles are not shown in the graphs of many questions. Now we introduce several methods of constructing isosceles triangles for readers’ reference. In the question graph, if there is an equal line segment of a common endpoint, there must be a hidden isosceles triangle available to connect the two points of the non-common endpoint.