“相交线与平行线”一节是新课程标准中“图形与几何”领域所要研究的基本问题.也是《三角形》、《全等三角形》、《相似三角形》、《平行四边形》等章节的基础内容.教材中在呈现本章内容时,让学生通过观察、测量、实验、归纳、对比、类比等来寻找图形中的位置关系和数量关系,从而发现图形性质,然后,通过推理获得数学结论.本文谈 The section “Intersecting Lines and Parallel Lines” is the basic problem to be studied in the new curriculum standard “Geometry and Geometry.” It is also a topic of “Triangle”, “Equal Triangle”, “Similar Triangle”, “Parallelogram” , Etc. In presenting the contents of this chapter, students should find out the relationship between the position and the quantity in the graph by observing, measuring, experimenting, inducing, comparing, analogy and so on, so as to find out the nature of the graph. Then, Mathematical conclusions