1. 3 Measuring Segments • Postulate 1. 3 – Ruler Postulate – Every point on a line can be paired with a real number. – The real number that corresponds to a point is called the coordinate of the point. – Allows you to measure lengths of segments and will allow you to find the distances between points. • The distance between points A and B is the absolute value of the difference of their coordinates.
Measuring Segment Lengths • • What is ST? What is SV? What is UV? What is TV?
Postulate 1. 3 Segment Addition Postulate • If three points A, B, and C are collinear and B is between A and C, then AB + BC = AC.
Using the Segment Addition Postulate • If EG = 59, what are EF and FG? EF + FG = EG EF = FG =
Using the Segment Addition Postulate • If EG = 59, what are EF and FG? EF + FG = EG (8 x – 14) + (4 x + 1) = 59 12 x – 13 = 59 12 x = 72 x = 6 EF = 8(6) – 14 = 34 FG = 4(6) + 1 = 25
Congruent Segments •
Comparing Segment Lengths •
• The midpoint of a segment is a point that divides the segment into two congruent segments. • A point, line, ray, or other segment that intersects a segment at its midpoint is said to bisect the segment. – The point, line, ray, or segment is called a segment bisector. A M B
Using the Midpoint • Q is the midpoint of PR. What are PQ, QR, and PR? • Find x. Find PQ and QR. PQ = QR= Find PR. PR = PQ + QR =