“等腰三角形”是三角形的认识中一个特殊性图形概念,是苏教版小学数学教材四年级下册第三单元的教学内容之一。这部分内容的教学一般按如下三个层次实施:第一层次是通过学生量三角形各条边的长度,理解“等腰”的含义;第二层次是仿照例题示范的方法,剪出一个等腰三角形,继续体会其中两边相等的关 “Isosceles triangle ” is a special graphic concept in the understanding of the triangle. It is one of the teaching contents of the third unit of the fourth grade undergraduates of the Supiao version of the primary school mathematics teaching materials. The teaching of this part of the content is generally implemented in the following three levels: The first level is through the length of each side of the triangle of students to understand the meaning of “isosceles ”; the second level is modeled on examples of demonstration methods, cut out a Isosceles triangle, continue to experience the same two sides off