The broken line is the figure in geometry consisting of the pieces which are consistently connected with each other through tops under different corners. The broken line can make the closed figure if the ends of extreme pieces coincide and also to cross itself.
Broken line consists from the tops and pieces connecting these tops. At the same time the main requirement – any two consecutive pieces do not lie on one straight line.
Compound pieces of a broken line are called its parties or links, and their ends – broken line tops. The smallest possible quantity of links of a broken line – two. Final tops of a broken line are called black dots.
Graphically the line is designated by names of its tops, for example, broken ABCDEFG. The broken line can be closed, i.e. its final tops coincide. Types of such line are polygons. The polygon is the flat closed broken line which has no self-crossings. Tops of a broken line are called polygon tops, and its links – the parties of a polygon. The polygon with three parties and tops is called a triangle. The closed broken line with four parties can be a square, a rectangle, a rhombus, a parallelogram, a trapeze. The figure with five and more parties is called the n-square where n is number of tops. The broken line can have self-crossings. A classical example of the closed broken line with self-crossings is the five-pointed star. A kind of the broken line is the zigzag in which pieces are parallel each other through one, and consecutive form an identical corner. Zigzags are used in sewing business and also at decorative registration of objects of use (ware, furniture, books) as an ornament. The broken line has broad application in cartography (creation of routes and the schematical image of streets), architecture (the line of buildings and home), landscaping (arrangement of paths, decorative registration), chemistry (molecular structures and connections), medicine (medical monitors for observation of a warm rhythm) and in other areas.