在研究几何中,我们时常发现一些有趣的性质,如三角形的同一个角的内角平分线和外角平分线分其对边及其延长线上的四条线段成比例.此性质充分揭示出三角形的同一个角的内角平分线和外角平分线之间的内在关系,即由内、外角平分线所截得的四条共线线段成比例,它为我们证明此类问题开辟了一条行之 In the study of geometry, we often find some interesting properties, such as the same corner of the triangle angle bisector and outer corner bisector is divided into four lines on the opposite side and its extension line is proportional to the nature of this fully revealed the same triangle The intrinsic relationship between the bisector of the inner angle and the bisector of the outer corner, that is, the proportion of the four collinear segments that are intersected by the bisector of the inner and outer horns, opens the door for us to prove such problems