一题多解既可使所学知识发生纵横联系,又能培养我们思维的广阔性、发散性、灵活性.现就课本习题举例如下. 例1 已知:梯形ABCD中,AD//BC,AB=DC求证:AC=BD.(几何第二册,第171页). 证法一如图1,直接证明△ABC≌△DBC,即可. 证法二如图2,过点C作CE//BD,交AD的延长线于E.证明△CDE≌△ABC即 A multi-solution to a question can not only bring about a vertical and horizontal connection, but also cultivate the broadness, divergence, and flexibility of our thinking. Now, examples of textbook exercises are given below. Example 1 Known: Trapezoidal ABCD, AD//BC, AB = DC Proof: AC = BD. (Geometry of the second volume, page 171). Proof of a Figure 1, directly proved △ ABC ≌ △ DBC, you can. Proof Act II Figure 2, over the point C for CE //BD, the extended line of AD is proved by E. △CDE ≌ △ ABC