一、了解一种数学思想多边形内角和公式的推导是通过添加辅助线将多边形分割为多个三角形,然后将多边形的内角和转化为我们所熟知的三角形内角和加以解决.像这种把陌生的问题转化为熟悉的问题加以解决的思想方法,在数学中称为化归思想,化归思想是数学研究与解题的重要思想之一,它在今后的学习中有着十分重要的应用. I. Understanding a Mathematical Thought The derivation of polygon inner angles and formulae is to add polygons to multiple triangles by adding auxiliary lines, and then to convert the interior angles of the polygons to the well-known triangle inner angles and solve them. This kind of strangeness is like this. The problem is transformed into a familiar problem to solve the thinking method, in mathematics is called the return to the idea, the return to the idea is one of the important ideas of mathematical research and problem solving, it has a very important application in the future learning.