在高中平面几何課中,有“正五互边形和五角星形的作图”的課題。关于它們的各种作图方法,有些已經在各个課本和杂志中提出来了。但是通过笔者向学員学习和下厂訪問,了解到一般工厂的工人在作有关正五边形的工业零件和画正五角星形的时候,还常常采用一些此較簡捷的近似作法。这种作法虽然从理論上說不够严密和精 In the high school plane geometry class, there are the topics of “positive pentagonal and pentagonal mapping.” Some of their various mapping methods have been proposed in various textbooks and magazines. However, when the author learned from the students and visited the factory, he learned that workers in general factories often use some simpler and more similar approaches when they make industrial pentagonal parts and draw pentagrams. Although this approach is theoretically not tight enough and precise