Draw any line segment, say . Take any point C lying in between A and B. Measure the lengths of AB, BC and AC. Is AB = AC + CB?

[Note: If A, B, C are any three points on a line such that AC + CB = AB, then we can be sure that C lies between A and B.]

Let’s draw a line AB and take a point C on it

As we can see AB is a line segment which starts with A and ends with B. C is a point on AB which means it divides AB in two parts. So sum of these parts will be equal to the total length of the line segments.

Hence, AB = AC+CB.