课例：三角形的内角和山东省滨州地区教研室王文清教学目标１．识记能说出三角形内角和等于１８０°及多边形内角和公式；２．理解能用多种方法独立推证三角形内角和定理；３．应用（１）用三角形内角和定理推证四边形、五边形、…、ｎ边形内角和公式；（２）用ｎ边形内角... Lessons: The internal angle of the triangle and Wang Wenqing, the teaching and research section of the Binzhou Region, Shandong Province The memorandum can say triangle inner angle equal to 180° and polygon inner angle and formula; 2. Understanding can use a variety of methods to independently verify the triangle angle and theorem; 3. Applications (1) use triangle internal angles and theorem to deduce quadrilateral, pentagonal,...,n-angle internal angles and formulas; (2) use n-angle internal angles...