当两个相似三角形的对应关系不确定时 (若表述为“以某三点为顶点的三角形与△ ×××相似”或表述为“△×××与△×××相似” ,则认为对应关系没有确定 .但表述为“△×××∽△ ×××”时 ,则已指明了对应关系 ) ,应从对应顶点、对应角或对应边的角度 ,分类讨论各种可能? When the correspondence between two similar triangles is indefinite (if the expression is “a triangle with some three vertices is similar to △ × × ×” or the expression is “△ × × × and △ × × × are similar”), the corresponding The relationship has not been determined. However, when the expression “△×××∽Δ×××” is used, the corresponding relationship has already been indicated). We should classify and discuss various possibilities from the perspective of the corresponding vertex, corresponding angle or corresponding edge.