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Mrs. McConaughy Geometry 1
Points, Lines, and Points, Lines, and PlanesPlanes
During this lesson, you will: Define and illustrate basic geometric terms Illustrate basic postulates of geometry
Mrs. McConaughy Geometry 2
Part I:Part I: Basic Basic Terms of Terms of GeometryGeometry
Mrs. McConaughy Geometry 3
In geometry, point, line, and plane are undefined terms. It is
important, however, to have general descriptions of their
meanings.
Remember: Points, lines, and planes are undefined terms.
They are the building blocks ofgeometry.
Mrs. McConaughy Geometry 4
Term Description/Real-
Life Model
Diagram
Symbol/Read:
Point
Line
Plane .
A location; has no sizeEx. _______
AB
C
Set of points extending infinitely in both directions
x
AMRead: “line AM”Read: “line x”
H
D.O. G.
A, B, CRead: “point __”
Read: “Plane H”Read: “Plane DOG”
Flat surface which extends infinitely in all directions
T EA
M
Mrs. McConaughy Geometry 5
VocabularyVocabulary
_______________________________________________________
__________________________________________
Collinear Collinear pointspoints
are two or more points
which lie on the same line.
coplanacoplanarr..
Points and lines which lie on the same plane are
Collinear Collinear pointspoints
Remember: Points, lines, and planes are _____________
They are the building blocks ofgeometry.
undefined terms.
Mrs. McConaughy Geometry 6
Identifying Collinear Points
Given the following sets of points, determine if they are collinear or non-collinear. If they are collinear, name the line on which they lie. Be sure to name each line at least two (2) ways.
a. W, O, Mb. W, E, Mc. W, N, E
WE
mn
lN
MO
Noncollinear
Collinear
CollinearName line l in three other ways.
Mrs. McConaughy Geometry 7
Checking for Understanding
1. Each surface of the ice cube represents part of a plane. Name the plane represented by the front of the ice cube.
2. List three different names for the plane represented by the top of the ice cube.
A
B
C
H
G
F
E
Mrs. McConaughy Geometry 8
Part II: Basic Part II: Basic Postulates of Postulates of
GeometryGeometry
Mrs. McConaughy Geometry 9
VocabularyVocabulary
A postulatepostulate or axiomaxiom _______________ ____________________________________________._____________________________.
is a statement which is accepted as being true.
Mrs. McConaughy Geometry 10
Line PostulateLine Postulate
Through any two points
_______________________________________.
there is exactly one line
Mrs. McConaughy Geometry 11
Line Intersection Line Intersection PostulatePostulateIf two lines intersect, ________________________________________then they intersect in exactly one point.
Mrs. McConaughy Geometry 12
Plane Intersection Plane Intersection PostulatePostulateIf two planes intersect, ________________________________________then they intersect in exactly one line.
A
B
You may find it to be helpful to use two note cards
to complete this postulate.
Mrs. McConaughy Geometry 13
Checking for Understanding
A
B
C
E
DG
F
1.What is the intersection of plane ABED and plane EBCF?
2. Name two planes that intersect in EF.
BE
DEFG BEFC
Mrs. McConaughy Geometry 14
Plane PostulatePlane Postulate
Through any three non-collinear points
_______________________________________.there is exactly one plane
W O
RK
Mrs. McConaughy Geometry 15
Checking for Understanding
Shade the plane that contains T, R, and M.
E
M
O
T
G
RY
Mrs. McConaughy Geometry 16
Homework Assignment
Pages 13-14: 1-23 odd; 31-43 odd; 48-51, 53-59 odd, 60-69, 70-72 all.
