正多边形的有关计算是初中几何的重要内容,学习这节内容应达到下述要求:会将正多边形边长、半径、边心距、中心角的有关计算问题转化为解直角三角形问题.然而,由于本节内容概念多,关系式多,许多伺学或难以把握要领,或计算出现偏差,从而影响了解题速度和结果。我们认为,学好本节内容应注意以下几个方面. 一、理解一个定理本节内容有一个定理:正n边形的半径和边心距把正n边形分成 The calculation of regular polygons is an important part of junior high school geometry. The content of this section should meet the following requirements: It will convert the calculation problems of regular polygon side lengths, radii, marginal center distances, and central angles into solving the right triangle problem. However, Since there are many concepts in this section and there are many relationships, many of them are either unable to grasp the essentials or calculating deviations, thus affecting the speed and results of the problems. We believe that learning the content of this section should pay attention to the following aspects. First, understand a theorem This section contains a theorem: the radius of the positive n polygon and the center-to-center distance divide the positive n edge into