Скачать или смотреть Lesson 07 Parallel and Perpendicular Lines

In this lesson you will learn about parallel and perpendicular lines. Lines are an important concept in Geometry. In geometry, a line is straight, has no thickness, and has infinite length. A line extends without end in both directions. Typically arrows are used to show that a line goes on forever. When two distinct lines extend in exactly the same direction they are called parallel lines. A pair of parallel lines always remains the same distance apart from each other. When a pair of lines are not parallel they always cross at one single point called the point of intersection, creating a set of 4 angles around this point. When these 4 angles are all right angles the two lines are called perpendicular lines. Although a line goes on forever, in many practical cases in geometry you will work with bounded sections lines called line segments. Line segments are the building blocks of polygons. Every polygon is composed of three or more line segments.