G1.2 notes

1.2 – Linear Measure & Precision
 Unlike a line, a line segment, or segment, can be measured because it has
two endpoints.
 A segment with endpoints A and B can be named as AB or BA .
 The measure of AB is written as AB.
 Recall that for any two real numbers a and b, there is a real number n
between a and b such that a  n  b . This relationship also applies to
points on a line and is called betweenness of points.
 Point M is between points P and Q if and only if P, Q and M are collinear
and PM  MQ  PQ .
 Notice that points R and T are not between points P and Q.
Example 1
a. Find LM.
b. Find XZ.
c. Find x and ST if T is between S and U, ST  7 x , SU  45 , and
TU  5x  3 .
 When segments have the same measure, they are said to be congruent.
KEY CONCEPT – Congruent Segments
Two segments having the
same measure are
 is read is congruent to.
Red slashes on the figure
also indicate that segments
are congruent.
L2 – pg 18 (22-33)