1. 1-2 Measuring & Constructing Segments
Geometry

2. Postulates
Rules that are accepted as _____ without having to be _________.
Sometimes they are called ________.

3. Postulate 1-2-1: Ruler post.
The points on a line can be matched with those on the real # line.
The real # that __________to a point is the coordinate of the point.
If you find the ____________ between the coordinates of 2 points, then take the absolute _______, 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 1: Find AB. A B Point A is at 1.5 and B is at 5.
So, AB = __ - __ =_____

6. Is Alex between Ty and Josh?
How about now?
In order for a point to be between 2 others, all 3 points MUST BE__________!!

7. Congruent ( ) Segments Segments that have the same length.
If AB & XY have the same length,
Then AB=XY,
but
AB XY
Symbol for congruent
Tick marks are used to show congruent segments

8. Post. 1-2-2: 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

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

10. Ex. 3) B is between A and C. Find AC.
A 3x -1 B C 6x

11. Reminder Midpoint is the ___________ point
Bisects or __________ the segment into two congruent segments.
Ex. 4) S is the midpoint of RT, RS = -2x, ST = -3x -2
Find RS = ___
ST = ___
RT = ___

12. Assignment

13. (x1,y1) & (x2,y2) are the 2 points.
1.3B Distance
Pythagorean Theorem –
a2+b2=c2
a & b are the lengths of the legs of a right triangle and c is the length of the hypotenuse.
Distance formula –
(x1,y1) & (x2,y2) are the 2 points.