中位线定理是几何证明部分常用的知识,包括三角形中位线和梯形中位线定理,定理的内容学生应该都了如指掌。在此类题中,一般不会直接给出中位线,甚至不能直接应用中位线定理解题,这就考验学生的想象力以及理论分析能力。本文分三点讨论在题中没有给出中位线的情况下,如何添加中位线以达到简便解题的目的。一、证明特殊图形的形状特殊的图形具有特殊的性质,也分别具有不同的证明方法,这就 The median line theorem is a part of the commonly used knowledge of geometric proof, including the bit-line theorem of bit lines in the triangle and the trapezoid. The theorem should be well understood by students. In such questions, the median line will not be given directly, and even the problem of using the median line theorem can not be solved directly, which tests students’ imagination and theoretical analysis ability. This article discusses three points in the title did not give the case of the median line, how to add the median line in order to achieve the purpose of simple solution. First, to prove the shape of special graphics Special graphics have special properties, but also have different methods of proof, which