与多边形有关的计算题,是初中数学中的一个知识点,屡见于各省市中考试题中。下面举几例供同学们参考。一、判定多边形的边数例1 已知一个多边形的内角和等于外角和的3倍,则这个多边形的边数为____。(1995年云南省中考题) 解设这个多边形的边数为n,则(n-2)×180°=3×360°,解之得n=8。例2 一个多边形的内角和与外角和的差为900°,则此多边形是____ The computational problems related to polygons are a knowledge point in junior high school mathematics and are often found in examination questions in various provinces and cities. Here are some examples for the students to refer to. First, determine the number of edges of the polygon Example 1 Known as the interior angle of a polygon and equal to 3 times the sum of the outer angle, then the number of sides of the polygon is ____. (Yunnan Provincial Examination Exam in 1995) The number of sides for solving this polygon is n, then (n-2)×180°=3×360°, and the solution is n=8. Example 2 The angle between the interior angle of a polygon and the sum of the outside corners is 900°, then this polygon is ____