1. Plane Geometry Unit 1 – Chapter 1
Section 1.2 – Use Segments and Congruence
Day 2

2. Section 1.2 Notes A B x1 x2 DISTANCE AB = |x1 – x2|
Postulate or Axiom – a rule that is accepted without proof.
Ruler Postulate
The points on any line can be matched to real numbers, that real number is known as the coordinate of that point.
The distance between any two points A and B, is written as AB and is the absolute value of the difference of the coordinates of A and B.
Names A B x1 x2
Coordinates
DISTANCE
AB = |x1 – x2|

3. Section 1.2 Notes AC A B C AB BC Segment Addition Postulate:
Between - is only when three points are collinear
If B is between A and C, then AB + BC = AC
If AB + BC = AC, then B is between A and C. AC A B C AB BC

4. Segments are congruent Mathematical Notation: Congruent
Section 1.2 Notes
Congruency: Congruent Segments – line segments that have the same length.
Equal vs. Congruence
AB = CD
lengths are equal
AB ≅ CD
Segments are congruent A B C D
Mathematical Notation: Congruent

5. Section 1.2 Notes W X Y Z Using the ruler postulate... Find:
Find:
1) WX 2) XY 3) WY 4) ZW W X Y Z

6. Section 1.2 Notes
Points G, H, I, J and K are collinear. GK = 24, HJ = 10, and GH = HI = IJ. Find each length
1) HI 2) IJ 3) GH
4) JK 5) IG 6) GK 24 G H I J K 10

7. Section 1.2 Notes
Find RS, QS, and TV using the following information: S is between T and V. R is between S and T. T is between R and Q. QV = 23, QT = 8, and TR = RS = SV V S R T Q 23 ? 8

8. Section 1.2 Notes
Point J is between M and N. Find the length of JM and JN given the following information. JM = 7x + 2, MN = 64, and JN = 2x – 1. So (7x + 2) + (2x – 1) = 64 9x + 1 = 64 9x = 63 x = 7 JM: 7(7) + 2 = 51 JN: 2(7) – 1 = 13 M J N 64
7x + 2
2x – 1

9. Section 1.2 Notes
Point M is between V and W. Find the length of VM and MW, given the following information. VM = 4x – 1, VW = 30, and MW = 3x + 3. So (3x + 3) + (4x – 1) = 30 7x + 2 = 30 7x = 28 x = 4 MW: 3(4) + 3 = 15 MV: 4(4) – 1 = 15 V M W 30
4x – 1
3x + 3

10. P. 10-11 #3 – 6 “Guided Practice”
CONCEPT CHECK
P #3 – 6 “Guided Practice”

11. HOMEWORK
P # (Omit #12)