Warm up (draw each one)
1) Vertical line m intersects a horizontal
plane M at point O.
2) Horizontal plane P contains two lines k
and n that intersect at point A.
3) Vertical planes X and Y intersect at line
AB.
4) Point P is not in plane N.
Segments
A line with two endpoints.
 It consists of the two endpoints and
those points in between.

AB
LABEL
AB
A
B
Rays


A ray has one endpoint and extends out
endlessly in one direction.
The endpoint (A) is always named first.
LABEL
AB
B
A
Number Line



COORDINATE – number associated with a
letter
Coordinate of M? 7
Coordinate of J? -4
J
A
M
Distance


The distance of a segment = length
LABEL
JA = ?6
AM = ?5
J
A
M
Segment Addition Postulate

If B is between A and C, then AB + BC = AC
A
B
C
CONGRUENCE


CONGRUENT: two objects that have the same
size and shape

Congruent Segments: segments with equal
lengths.
12.4
12.4
MIDPOINT
Midpoint of a Segment:
 is the point that divides the segment into
two congruent segments.
BISECTOR
Bisector of a segment:
is a line, segment, ray, or plane that
intersects the segment at its
midpoint.
Find x if RA = 2x + 4, AY = 3x + 1,
and RY = 30.
Z
R
2x + 4 A
3x + 1
30
C
2x + 4 + 3x + 1 = 30
5x + 5 = 30
5x
- 5 = 25
-5
/5x = 5/5
Y
PRACTICE
 Page
14
 Classroom
 #1
– 20
Exercises