多边形是由线段首尾相接所构成的几何图形.根据构成多边形的线段的条数,多边形分为三边形(习惯上称为三角形)、四边形、五边形……其中三角形是最简单的多边形,也是最基本的多边形,它在几何图形中占有重要的地位.一、认识三角形是认识多边形的基础说三角形是最简单的多边形,是因为它在多边形中边数最少,内角最少,没有对角线,因此图形最 Polygons are the geometric shapes formed by the end-to-end links of a line segment. Polygons are classified into three types of triangles (conventionally called triangles), quadrangles, pentagons, etc., depending on the number of segments that make up the polygon ... where triangles are the simplest polygons , Is also the most basic polygons, which occupy an important position in the geometry.First, recognize the triangle is the basis for understanding polygons that the triangle is the simplest polygon, because it is in the polygon in the least number of edges, the smallest internal angle, there is no diagonal Line, so most graphics