2. Finding Segment Lengths

3. Absolute value of their difference

4. Example 1: Comparing Segments Lengths

5. Check Understanding

6. Midpoint

7. Segment Addition Postulate If you divide a line segment into two pieces, they must add up to the original length of the line segment. AB C

8. 6 3.5 3 62 9 x = 4 x = 9 Algebra Review

9. Example 3: Finding Lengths

10. Check Understanding XZ + ZY = XYSegment Addition Postulate x + x = 27Substitute 2x = 27Simplify x = 13.5Divide both sides by 2 So XZ = 13.5

11. Example 2: Using the Segment Addition Postulate If DT = 60, find the value of x. Then find DS and ST.

12. Check Understanding EG = 100. Find the value of x. Then find EF and FG. 4x – 20 + 2x + 30 = 100 Segment Addition Postulate 6x + 10 = 100 Simplify like terms 6x = 90 Subtract 10 from both sides x = 15 Divide each side by 6 EF = 4x – 20 = 4(15) – 20 = 40 Substitute 15 for x FG = 2x + 30 = 2(15) +30 = 60

13. 1-3 Quiz The following questions are a review of what we covered today. They are designed to help you determine whether or not you understood the new concepts. Please make sure you make time to come and see me if you are missing more than you are getting right!

14. A. x = 3, EF = –6, FG = –6 B. x = 10, EF = 8, FG = 15 C. x = 10, EF = 32, FG = 45 D. x = 3, EF = 8, FG = 15

15. A. x = 10, ST = 60 B. x = 5, ST = 60 C. x = 10, ST = 45 D. x = 5, ST = 45

16. 3. Which point is the midpoint of AE ? A. D B. B C. Not B, C, or D D. C

17. 4. What is the length of AE ? A. 14 B. 2 C. 8 D. 48

18. 5. Find AC. A. 14 B. 15 C. 12 D. 4