前不久,笔者在我市一次“名师送教”活动中,观摩了一节课,课题是人教版数学九年级“位似”.授课教师上课激情四射,幽默风趣,通过创设情景,带领学生逐步归纳得到位似的概念,设置丰富的练习巩固技能,探究了位似性质,研究了如何利用位似将图形放大或缩小,可谓一气呵成,扎实而高效.特别是,针对课本的定义“两个多边形不仅相似,而且对应顶点的连线相交于一点,对应边互相平行,像这样的两个图形 Not long ago, the author witnessed a class in the city’s once-in-a-day ”teacher teaching“ activity. The subject was the 9th grade of mathematics of the People’s Education Press. ”The position resembles “. The instructors are enthusiastic in class and humorous. Creating scenarios, leading students to gradually obtain a concept of similarity, setting up a wealth of practice and consolidating skills, exploring the nature of similarities, and studying how to use bits to enlarge or reduce the graphics, which can be described as one-stop, solid and efficient. In particular, against textbooks The definition of ”two polygons is not only similar, but also the corresponding vertices intersect at a point, the corresponding sides are parallel to each other, like these two graphics