十年前,我一开始接触初中数学教材,发现课本中有三角形三条角平分线交于一点、三边垂直平分线交于一点的证明,但没有三角形三条中线、三条高交于一点的证明.这是为什么?难道没有初中生能理解的相应证明吗?当时想,可能没有,于是就这样过去了几 Ten years ago, when I first came into contact with junior high school math teaching materials, I found that there are tessellations in the textbook that the bisector of the three angles of the triangle intersect at one point and the perpendicular bisector of the three sides at one point. However, there is no proof that the middle three triangles and the three highs intersect at one point. This is why? Is not there junior high school students can not understand the corresponding proof? At that time, may not, so it passed