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1.2 Use Segments and Congruence. 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 = | x 2 – x 1 |. A. B. x 1. x 2. Segment Addition Postulate. If B is between A and C then. AB. = AC.
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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
Segment Addition Postulate • If B is between A and C then AB = AC + BC AC AB BC C A B
Congruent Segments • Two segments are congruent if they have the same length. A B 12 D C 12 AB is congruent to CD AB = CD ~
N M P Q • 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? • MN is the line segment itself • MN means the length of the line segment • PN = PQ + QN = 4 + 5 = 9 • PN = MN – MP = 14 – 3 = 11
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 = 6 - 2 = 4 ~ AB = CD JK = -2 – (-8) = -2 + 8 = 6 LM = -6 – (-2)= -6 + 2 = |-4| = 4 ~ JK ≠ LM