Learn about Classification of Lines In this lesson, let’s learn how to classify lines. And we classify each pair of the lines given below as either intersecting, perpendicular or parallel which means I got to know how to do these three things do. What are intersecting lines? Well, let’s learn about those first. Intersecting lines are when two lines are on the same plane. And cross each other once. In this case, we can see A, B, C and D are two lines that extend in both directions. There infinite, right. Well they intersect once, so this is called an intersecting line, intersecting pair of lines. That’s the first one. Second are parallel lines. Parallel lines are all on the same plane, right but they can never intersect which means even if I extend them infinitely in both directions. They will never cross each other, right. They will never cross that’s because at any point, the distance between the two lines is the same. So if we look at this, right, the distance here and the distance here is exactly the same. If the distance between two lines is the same at any given point no matter how far we go, these are called parallel lines. Parallel lines will never cross each other. Now if two lines crossed each other as we can see here, right and they formed right angles. Four different right angles, then they are called perpendicular lines. Perpendicular lines crossed each other, they’re intersecting lines but they intersect at a 90 degree or a right angle, in that case called perpendicular lines, pretty simple. If the lines intersect or cross each other once, they called intersecting. If they never intersect and never can intersect, they are parallel. If they intersect exactly at a right angle, it will form four right angles then they are perpendicular.