平行四边形作为一种特殊的四边形,它具有对边平行且相等、对角线互相平分、对角相等、两邻角互补等性质.在证明线段的相关问题时,同学们要认真审题,明确题意要求,仔细观察图形特征,灵活巧妙地添加辅助线构造平行四边形,架设证明线段问题的桥梁,从而简化证明过程,提高解题效率.一、构造平行四边形证线段相等当要证明的两条相等线段共处于一个四边形时,可先证明这个四边形为平行四边形;若平行四边形条件不好找,可以结合题目特 Parallelogram as a special quadrilateral, it has the opposite side parallel and equal, diagonals equal to each other, the same diagonal, two adjacent corners of the nature of complementarity, etc. In demonstrating the relevant issues in the line, the students should seriously examine questions, clear questions Italian requirements, careful observation of graphic features, flexible and ingeniously added auxiliary line structure parallelogram, set up a bridge to prove the problem of line segment, thus simplifying the proof process and improving the efficiency of problem solving.First, the construction of parallelogram segments equal to prove two equal When the line is in a quadrilateral, you can prove that the quadrilateral is parallelogram first. If the condition of parallelogram is not easy to find, you can combine the special