Mrs. McConaughyGeometry1 Points, Lines, and Planes During this lesson, you will: Define and...

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

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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

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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

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VocabularyVocabulary

A postulatepostulate or axiomaxiom _______________ ____________________________________________._____________________________.

is a statement which is accepted as being true.

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Line PostulateLine Postulate

Through any two points

_______________________________________.

there is exactly one line

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Line Intersection Line Intersection PostulatePostulateIf two lines intersect, ________________________________________then they intersect in exactly one point.

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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.