教学内容:人教版四年级下册。教学目标:1.在观察、操作活动中能概括并理解三角形的意义,认识三角形的各部分名称。2.知道三角形底和高的含义,会画三条底边上的高,会用字母表示三角形。3.了解三角形的稳定性及其应用。4.培养学生善于观察,勤于思考的好习惯。教学重点:理解三角形的定义及特性。教学难点:会画三角形三边对应的高。教学准备:教师:课件、三角形框架、四边形活动框架、直尺。 Teaching content: PEP fourth grade. Teaching Objectives: 1. In the observation, operational activities can summarize and understand the meaning of the triangle, recognize the name of each part of the triangle. 2. Know the meaning of the triangle at the bottom and high, will draw the height of the three bottom, will use letters to represent the triangle. 3. Understand the stability of the triangle and its application. 4. Cultivate students good at observation, diligent in thinking good habits. Teaching Point: Understand the definition and characteristics of the triangle. Difficulties in teaching: Will draw the triangular high corresponding to the three sides. Teaching preparation: Teacher: Courseware, triangle frame, quadrilateral activity frame, ruler.