圆中等积式的证明虽是一个常见题型,但仍有不少同学望而却步,究其原因,多半是由于对该类问题没有一个明确的分析思路造成的.其实这类问题只要抓住相似三角形,灵活应用某些代换是不难解决的.现以近年的中考题为例来说明,望对同学们有所启迪.一、直接证相似结论中的等积式,可直接通过证明三角形相似得到. However, there are still many students who are discouraged because of the fact that most of them are due to the lack of a clear analysis of such problems. In fact, such problems should be seized by similar triangles , Flexible application of some substitution is not difficult to solve. Now in recent years, the examination questions as an example to illustrate the enlightenment of the students. First, the direct card similar conclusions in the same, can be directly proved by the triangle similar get.