1. Segments, Rays,
& Distance
Section 1-3

2. And Now, for Some New Definitions
Segment – two points on a line and all the
points between them
B C
Segment BC, or… BC
B and C are the endpoints of BC.
In geometry, between means “on the line connecting.”

3. More New Definitions
Ray – one point on a line and all the points
extending in one direction only
C K
Ray CK, or… CK (not KC!!!)
C is the endpoint of CK.

4. More New Definitions
Opposite rays – rays that extend in opposite
directions along the same line from a
common endpoint
X Y Z
YX and YZ are opposite rays.

5. More New Definitions
Length – the distance from one point to another
X W Y Z
• • • •
-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8
The length of XY is denoted XY.
To find lengths on a number line, take the absolute
value of the difference of the coordinates of the endpts.:
XY = 3−(−5) =8 OR XY = −5−3 =8
Distance must be positive.

6. More New Definitions
Postulates – statements accepted
without proof; also called axioms
Congruent – having the same size
and shape
congruence symbol:

7. More New Definitions
Congruent Segments – segments of equal length
•N
10 cm P• 10 cm
•M
L•
To show congruence
in the diagram
The segments have Which means that they
equal lengths: are congruent:
LN = MP LN = MP

8. More New Definitions
Midpoint of a Segment – point that divides a
segment into two congruent segments
• • •
A B C
If AB = BC, then
B is the midpoint of AC.

9. One More Definition
Segment Bisector – a line, segment,
ray, or plane that intersects a
segment at its midpoint

10. Let’s Practice!!!
Look to your textbooks, page 14, #1-14