1. 1.2 Use Segments and Congruence

2. The Ruler Postulate
The distance between two points on a line is the absolute value of the difference of the coordinates of the two points.
AB = |x2 – x1| A B x1 x2

3. Segment Addition Postulate
If B is between A and C then AB
+ BC
= AC AC AB BC A B C

4. Congruent Segments
Two segments are congruent if they have the same length. A 12 B C D 12
AB is congruent to CD
AB = CD ~

5. If PQ = 4 and QN = 5, what is PN? If MP = 3 and MN = 14, what is PN?
Explain what MN means and what MN means.
If PQ = 4 and QN = 5, what is PN?
If MP = 3 and MN = 14, what is PN? M P Q N
MN is the line segment itself
MN means the length of the line segment
PN = PQ + QN = = 9
PN = MN – MP = 14 – 3 = 11

6. Plot the points then tell whether the line segments are congruent.
1. A(0, 1), B(4,1), C(1,2), D(1,6) AB & CD?
2. J(-6,-8), K(-6,-2), L(-2,-4), M(-6,-4) JK & LM?
AB = 4 – 0 = 4
CD = = 4
AB = CD ~
JK = -2 – (-8) = = 6
LM = -6 – (-2)= = |-4| = 4 ~
JK ≠ LM