1. Line Segment
A line segment consists of two points called endpoints of the segment and all the points between them. A D H

2. Segments that have the same length.
Congruent Segment
Segments that have the same length. A D H

3. Postulate vs. Theorem Postulate – a rule accepted without proofs.
Theorem- a rule that must be proven.

4. Segment Addition Postulate
States that given two points A and C, a third point B lies on the line segment AC if and only if the distances between the points satisfy the equation AB + BC = AC. A B C

5. In order for you to say that a point B is between two points A and C, all three points must lie on the same line, and
AB + BC = AC.
C: CD + DR = CR

6. Using Segment Addition Postulate, answer the following questions:
Example 1: If DT = 60, find the value of x. Then find DS and ST.

7. Segment Addition Continued:
Example 2: If EG = 100, find the value of x. Then find EF and FG.

8. Example 3: Using the Segment Addition Postulate
M is between N and O. Find NO. 27

9. Example 4: Draw a picture and solve for the missing segment.
B is between A and C, AC = 14 and BC = Find. AB

10. Example 5: Draw a picture and solve for the missing segment.
Find RT if S is between R and T. RS = 2x + 7, ST = 28 and RT = 4x.

11. Midpoint of a segment:
The midpoint of a segment is the point that bisects, or divides, the segment into two congruent segments.
Example: C is the midpoint of and

12. Segment bisector:
Example 6: BC = 3x + 2 and CD = 5x – 10. Solve for x. What is the length of BD?

13. Segment bisector:
Example 7: AC = 5x - 16 and CF = 2x – 4. Solve for x. What is the length of AF?

14. Complete worksheet