Definition
Point: a location in space. A point has
no size, but is represented by a dot
labeled with a capital letter.
A
Q
Z
P
Definition
Space: the set of all points
Definition
Line: a series of points that extends without
end in two opposite directions.
l
Q
P
Definition
Collinear: points that lie on the same line.
R
Q
P
Practice
In the figure below, name three points that are collinear and
three points that are not collinear.
Points Y, Z, and W lie on a line, so they are collinear.
For example, X, Y, and Z and X, W, and Z form triangles and
are not collinear.
Definition
Plane: a flat surface that extends in all
directions without end.
Practice
Shade the plane that contains X, Y, and Z.
Practice
Name the plane shown in two different ways.
You can name a plane using any three or more points on
that plane that are not collinear. Some possible names for
the plane shown are:
plane RST
plane RSU
plane RTU
plane STU
plane RSTU
Definition
Coplanar: points and lines that are in the
same plane.
Practice
1.
How many planes are represented by the
surfaces of the cube?
2.
Name the plane of the front of the cube in two different
ways.
3.
Name a point that is coplanar with the given points:
a.
E, F, G
b.
B, C, G
Definition
Postulate: an accepted statement
of fact.
Four Basic Postulates
1-1: Through any two points there is exactly one line.
1-2: If two lines intersect, then they intersect in exactly
one point.
1-3: If two planes intersect, then they intersect in a line.
1-4: Through any three noncollinear points there is
exactly one plane.
Homework
Points, Lines, and Planes in
Student Practice Packet
(Page 3, #1-21)