塞瓦定理的角元形式在处理一些平面几何问题时往往能够发挥很强的功效,本文枚举数例加以说明.角元形式的塞瓦定理:设D,E,F分别是ΔABC的三边BC,CA,AB或其延长线上的点,则AD,BE,CF三线平行或共 The angular form of the Seva theorem can often play a very powerful role in dealing with some plane geometry problems, and the enumeration examples in this article illustrate the Ceva theorem of the diagonal form: Let D, E and F be the three sides of the ΔABC BC, CA, AB or the extension of its point on the line, then AD, BE, CF three lines parallel or in total