平行线分线段成比例定理的推论:平行于三角形一边的直线截其他两边(或两边的延长线)所得的对应线段成比例以及定理:平行于三角形一边的直线和其他两边(或两边的延长线)相交,所成的三角形与原三角形相似.可以简记为“平行(?)相似”.它们反映在下面两个图形上.即“(?)”和“(?)”我们称之为基本图形.为了叙述 Parallel reasoning of the proportionality theorem of parallel segments: the parallelism of one side of the triangle is proportional to the corresponding segment of the other two sides (or the extension of both sides) and the theorem: the straight line parallel to one side of the triangle and the other two sides ), And the resulting triangles are similar to the original triangle, which can be abbreviated as “parallel (?) Similar”. They are reflected in the following two graphics: “(?) ” And “ ”We call it basic graphics. To narrate