1. Bellwork
4) Suppose you know PQ and QR. Can you use the segment addition postulate to find PR? Explain.

2. 1-3 Measuring Segments and Angles

3. Postulate 1: Ruler post.
The points on a line can be matched with those on the real # line.
The real # that corresponds to a point is the coordinate of the point.
If you find the difference between the coordinates of 2 points, then take the absolute value, you will have the distance between the points.

4. Ruler post. (continued)A B x1 x2
The length of AB can be found by x2-x1
**The symbol for the length of AB is AB.

5. Example: Find AB. A B Point A is at 1.5 and B is at 5.
So, AB = = 3.5

6. Is Alex between Ty and Josh?
Yes! Ty
Alex
Josh
No, but why not?
How about now?
In order for a point to be between 2 others, all 3 points MUST BE collinear!!

7. Post. 1-6: Segment Addition Post.
If B is between A & C, then
AB + BC = AC.
If AB + BC = AC, then B is between A & C. C B A

8. EX.
If EG= 59, what are EF and FG?
8x-14 E F
4x+1 G

9. OYO.
If EG= 120, what are EF and FG?
4x+6 E F
7x+15 G

10. Ex: if DE=2, EF=5, and DE=FG, find FG, DF, DG, & EG.

11. Segments that have the same length. If AB & XY have the same length,
Congruent ( ) Segments
Segments that have the same length.
If AB & XY have the same length,
Then AB=XY,
but
AB XY
Symbol for congruent

12. Midpoint- a point that divides the segment into two congruent segments
Segment Bisector- a point, line, or ray that intersects a segment at its midpoint

13. Ex..
Q is the midpoint of PR. What are PQ,QR, and PR?
6x-7
5x +1 P Q R