一道求证等积式的习题,往往使一些同学感到无从下手,大有“山重水复疑无路”之感。这是对求证的习题的规律和方法掌握不熟练或运用不灵活的缘故,然而若架起相似三角形这座桥梁,就会看到“柳暗花明又一村”了。现将这种题型的证明方法略举几例,供同学们复习时参考。 A series of exercises that seek to identify isogradual problems often make some students feel that they have no way of starting. This is due to the incompetence or inflexible use of the laws and methods for verifying the exercises. However, if a bridge of similar triangles is erected, you will see the village of Liuyinhuaming. Now we will give a few examples of this type of proof, for reference when students review.