Point, Line Segment, Line and Ray

Class 6 Maths · Chapter 2: Lines and Angles · NCERT Ganita Prakash section 2.1–2.4

Learn

Geometry starts with the point: an exact place, with no size at all. We show it with a tiny dot and give it a capital letter as its name: point Z, point P, point T.

Mark two points A and B. Of all the routes from A to B, the shortest one is the line segment AB (or BA). A and B are its end points. A fold in a sheet of paper gives the idea of a line segment.

Now extend segment AB beyond A and beyond B, without end. That is a line AB. It is drawn with arrows at both ends, and is sometimes named with a small letter like l or m. We can never draw all of it!

Through one point, endlessly many lines can pass. Through two points, exactly one line passes.

A ray starts at one point and goes on endlessly in one direction, like the beam of a torch or a lighthouse. Ray AP starts at A and passes through P. The starting point is always written first.

Explore: use the geo board. Pick a tool, then tap two points to draw.

1. Draw the line segment AB.
2. Draw the ray CD (it starts at C and goes through D).
3. Draw the line BD.

Remember

• Point: an exact location, named with a capital letter.
• Line segment AB: the shortest path from A to B; two end points.
• Line: goes on forever in both directions. Ray: starts at a point and goes on forever in one direction.
• Exactly one line passes through two points.

Quick check

Which of these has exactly two end points?

1. Line
2. Ray
3. Line segment
4. Point

Think about it

Ray OA starts at O and passes through A, and also through B. Can you call it ray OB? Can you call it ray AO?

Practice

Practise with fresh questions at three levels (easy, medium, hard), some answered hands-on, with hints and worked answers. Get 4 of your last 5 right to finish the topic.