在已知圓內作內接五角星的方法,据我所知有兩种:一为將圓半徑分成中外比,用其中項將圓十等分,然后从任一分点起每隔三分点連結之,即得所求的五角星形(見吉西略夫著之高中平面几何教科書第二章正多边形和圓)。其二法是根据下面的定理:“圆內接正五边形一边的平方,等于其內接正十边形的一边与該圓半 In the known circle, there are two methods for inward connection of five-pointed stars: as far as I know, there are two types: one is to divide the circle radius into Chinese-foreign ratios, divide the circle ten minutes with the item, and then every three minutes from any point. Points are connected, that is, the pentagram (see Gisielov’s High School Plane Geometry Textbook Chapter 2 Regular Polygons and Circles). The second method is based on the following theorem: "The circle is connected to the square of one side of the regular pentagon, equal to the side of the square with the regular decagon and the half of the circle.