《四边形》一章是对前面所学几何知识的应用和深化,对同学们的推理证明能力要求较高,在学习过程中,许多原来觉得困难的证明题,如果巧用面积法中的“等底等高的三角形等积”等定理,则可迎刃而解. The chapter “Quadroglyx” is the application and deepening of the knowledge of the geometry learned in the previous chapter. It requires a higher level of proof for the students’ reasoning ability. In the course of learning, many of the original problems that were found to be difficult to use are “what if? The equal triangle theorem, etc., can be easily solved.