Section 1 – 1
Identify Points,
Lines, and Planes
Definition:
Facts/Characteristics:
Has no dimension
and is represented
by a dot.
Examples:
Name a point on the
line
Points A, B or C
●A
Point
point A
Non-examples:
Definition:
Facts/Characteristics:
Has one dimension
and is represented
with two arrowheads
and extends
without end.
Written like this:
Line l, line AB,
line BA
Line
Examples:
Write the line 3 ways
m
D
E
Line m, line DE,
line ED
Non-examples:
Definition:
Facts/Characteristics:
Has two dimensions and
is represented by a shape
that looks like a floor or Plane F, or Plane
a wall and extends
ABC
without end.
Plane
Examples:
Two other names for
plane l
Plane ABC
Plane CAD etc.
Non-examples:
Definition:
Facts/Characteristics:
Points that lie on the
same line.
Points A, B, and C
are all collinear
Collinear
points
Examples:
Non-examples:
Name two collinear points
Points A & D
Points C & E
are not collinear.
Points A, B, E
Points D, B, C
Definition:
Points that lie on
the same plane
Facts/Characteristics:
Points A, B, and C
are all coplanar
Coplanar
Examples:
points
Name 3 coplanar points
Points G, E, O, B
Points F, A, L, I, C
Non-examples:
Points G and F are not
coplanar
Points O and L are not
coplanar
Definition:
Facts/Characteristics:
Part of a line
defined by two
endpoints.
Examples:
Written as:
AB or BA
Segment
What’s another name
for CD
DC
Non-examples:
Watch your symbols:
CD is not CD
Definition:
Part of a line from
a point in one
direction without
end.
Facts/Characteristics:
Written:
ray AB
Written:
Ray
Examples:
Name rays with
endpoint B
Rays BA, BC
BD, BE
Non-examples:
ray BA
Definition:
Facts/Characteristics:
Two connected rays
going in opposite
directions. Opposite
rays make a line.
Examples:
Opposite
Rays
Name 2 sets of opposite
rays
Rays BC and BD
Rays BA and BE
Rays CA and CB
are opposite
Non-examples:
Definition:
Facts/Characteristics:
Two lines intersect
Location where
at
a
point.
two geometric
Two planes intersect
figures have
in a line.
point(s) in
common.
Intersection
Examples:
Lines DC and AB
intersect at point E
Planes Q and P
intersect at line AB
Non-examples:
Homework
Section 1-1
Page 5 – 6
1 – 6,
8 – 12,
17, 18, 20,
25, 26