《三角形》一章中 ,部分概念似是而非 ,学生难以作出正确判断 ,在复习中应予以足够重视。一、三角形的中线和中位线三角形的中线是顶点和对边中点间的线段 ;而中位线是两边中点间线段 ,因此两者有着本质的区别。但在特定的图形中它们具有特定的位置关系或数量关系。例 1.如图△ In the chapter “Triangle”, some of the concepts are plausible. Students find it hard to make correct judgments and should pay enough attention to the review. First, the middle line of the triangle and the middle line of the triangle The middle line is the line between the vertex and the middle point on the opposite side; while the median line is the line segment between the two sides of the center, so the two have essential differences. However, in a particular graphic they have a specific positional relationship or a quantitative relationship. Example 1. Figure △