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生活中许多美妙的图形,是由线和角构成的.在《平面图形的认识(一)》这一章中通过丰富的实例,我们认识了线段、射线、直线、角等简单的平面图形,了解了平面上两条直线的平行与垂直关系,这些都是进一步研究其他图形性质的基础.一、线段、射线、直线1.线段、射线、直线的区别与联系线段、射线、直线的区别在于有无延伸性和有无端点,线段向一方无限延长形成射线,向两方无限延长形成直线.在用符号表示线段、射线、直线时,一般应在字母
Many of the wonderful graphics in life are made up of lines and corners. In the chapter “Cognition of Planar Graphics (1)”, through rich examples, we have learned simple plane graphics such as line segments, rays, lines, and angles. Understand the parallel and perpendicular relationship between two straight lines on the plane, these are the basis for further study of other graphic properties. 1. Line segment, ray, line 1. The difference between line segment, ray, and line is different from the line segment, ray and line. With or without extensibility, the line segment extends indefinitely to one side to form a ray, extending indefinitely to form a straight line on both sides. When a line, a ray, or a line is represented by a symbol, it should generally be in the alphabet.