平面几何的有关问题,其实质是定理通过图形的再次呈现,综合推证出一个结论,因此平几教学要求学生熟悉定理(性质等)与图形的对应(包括两层意思:一是要掌握一个定理适用的图形条件,二是要知道某一具体图形具备运用哪一个定理的条件),能够根据题目中的条件、待证结论、图形,选用可行的定理、性质作为依据,或根据条件,待证结论,可用定理构造(添辅助线)或从复 The essence of the problem of plane geometry is that the theorem is presented again through the presentation of the graph and comprehensively deduce a conclusion. Therefore, the teaching of Ping Ping requires students to be familiar with the correspondence between the theorem (nature, etc.) and the graph (including two meanings: one is to master one Theorem applies to the graphical conditions, the second is to know which specific theorem has the condition of which theorem to use), can be based on the conditions in the title, the conclusions to be proved, the graph, select the feasible theorems, properties as the basis, or according to the conditions to be Conclusion, theorem can be used to construct (add auxiliary line) or from the complex