Unit 1 Section 2 Segment Addition Postulate

Unit 1 Lesson 2

Segment Addition Postulate

Look at the figure given below and
answer the questions.

(i) Name three points that are
collinear.

(ii) name four points that are
coplanar.

(iii) Name three points that are not
collinear.

Unit 1 Lesson 1 Review (Collinear & Coplanar)

​(G.CO.A.1)

What is a Number Line?

In math, a number line can be defined as a straight line with numbers placed at equal intervals
or segments along its length.A number line can be extended infinitely in any direction and is
usually represented horizontally.

The numbers on the number line increase as one moves from left to right and decrease on
moving from right to left.

​(G.CO.A.1)

Segment Addition Postulate Defined

The segment addition postulate states that if we are given two points on a line segment, A and C, a third point B lies on
the line segment AC if and only if the distances between the points meet the requirements of the equation AB + BC = AC.
See Diagram 1 to gain a clearer understanding of this postulate definition.

Remember that a line segment is part of a line bound by two clear end points. It is comprised of a bunch of points between

those two endpoints.

An easier way of stating the segment addition postulate is that if point B lies on line segment AC, then AB + BC will equal

AC. That seems pretty simple, does it not?