三角形的内角和是三角形的一个重要性质,是进一步学习的基础。教材先通过让学生分别度量不同类型的三角形的内角度数,再算出每个三角形内角的和各是多少度,初步感知它们的和大约是180°,再引导学生用剪拼等实验方法来验证,进而概括出结论。由于该内容适合于让学生动手操作,且理解和掌握的难度不大,因此,它成了许多名师公开教学的重要内 The interior angle of the triangle is an important property of the triangle and is the basis for further study. Teaching materials first by allowing students to measure the different types of triangles within the angle, and then calculate the angle of each triangle and how many degrees, the initial perception of them and is about 180 °, and then guide students to use such as experimental methods to verify , Then summarize the conclusion. As the content is suitable for students to operate, and difficult to understand and grasp, therefore, it has become an important teacher open teaching many important