“三角形的内角和”是三角形的一个重要性质,是“空间与图形”领域的重要内容之一,学好它有助于学生理解三角形内角之间的关系,也是进一步学习几何的基础。本课是在认识了教学三角形的基本特征,三角形的底和高,三角形的分类后安排的教学内容。教学的重点是让学生探究、猜 “Triangle and ” triangle is an important property of the triangle is one of the important areas of “space and graphics ”, learning it helps students understand the relationship between the internal angles of the triangle is also the basis for further learning geometry . This course is based on the understanding of the basic characteristics of the teaching triangle, triangle bottom and high, triangular arrangement of teaching content. The focus of teaching is to allow students to explore and guess