在物理解题中,常会遇到这样一类问题:某物理量的变化量与它相关的物理量的变化是成正比的.对此类问题,若巧用初中《几何》上所学的“平行线截线段成比例定理”(简称“截比”定理)来求解,就会使抽象的物理问题转变成直观的几何图形,从而便于快速、准确的解答.尤其在速解填空和选择类问题时具有独特的妙用.现介绍此法如下. In physical understanding questions, one often encounters the problem that the amount of change in a physical quantity is directly proportional to the change in its associated physical quantity. For such problems, if we use the “parallel” in junior high school “geometry” The linear theorem (the abbreviation “cut ratio ” theorem) to solve, will make the abstract physics problem into an intuitive geometry, so as to facilitate fast and accurate solutions. Especially in the short-term solution and fill in the blanks and select The class problem has a unique magical effect. Now this method is introduced as follows.