小学数学课本第七册几何初步知识部分关于三角形的教学,对学生以后学习几何、三角等,起打基础的作用。三角形的教学必须十分重视。下面谈谈三角形的教学。一、关于三角形的概念教学中,要使学生明确地认识三角形。什么是三角形?课本上说:“由三条线段围成的图形叫做三角形”。什么样叫“围成”?就是三条线段首尾相接的封闭图形。图1是三角形,图2或图3都不是三角形。可叫学生 Elementary mathematics textbook The seventh volume of geometry Initial knowledge about the teaching of the triangle, the students learn geometry, the triangle, play a fundamental role. Triangle teaching must attach great importance. Here to talk about the triangle teaching. First, the concept of the triangle teaching, to enable students to clearly understand the triangle. What is a triangle? Textbook said: “The figure surrounded by three lines is called a triangle.” What is called “encircled”? Is the end of three lines connected to the end of the closed graphics. Figure 1 is a triangle, neither Figure 2 nor Figure 3 is a triangle. Can be called a student