# Points, Lines and Planes Contributed by: This pdf includes the following topics:-
Undefined Terms
Plane
LINE
Defined Terms
Segment
Ray
Examples
1. Identify Points Lines
and Planes
Essential Question: How
do you name
geometric figures?
We will write and discuss geometric figures.
2. Undefined Terms
• Undefined terms are words that do not have
formal definitions, but there is agreement
• The three undefined terms in geometry are
point, line, and plane.
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
3. Point
A point has no dimension. It is represented by a
Point A
.A
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
4. Line
A line has one dimension. It is represented by a
line with two arrowheads, but extends without
Through any two points there is exactly one line.
You can use any two points on a line to name it.
l .A .B Line l, line AB (𝐴𝐵),
line BA (𝐵𝐴),
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
5. Plane
A plane has two dimensions. It is represented by a
shape that looks like a floor or a wall, but it extends
without end.
Through any three points not on the same line
there is exactly one plane. You can use three points
that are not all on the same line to name a plane.
M
.A Plane M or Plane ABC
.B .C
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
6. Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
7. Defined Terms
• Terms that can be described using known
words such as point or line.
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
8. Segment
The line segment AB, or segment AB, (written
𝐴𝐵) consists of the endpoints A and B and all
points on 𝐴𝐵 between A and B.
.B
Endpoint
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
9. Ray
The ray AB (written 𝐴𝐵) consists of the endpoint
A and all points on 𝐴𝐵 that lie on the same side
of A as B.
Note that 𝐴𝐵
.A .B and 𝐵𝐴 are
different rays.
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
10. Opposite Rays
• If point C lies on 𝐴𝐵 between A and B, then
𝐶𝐴 and 𝐶𝐵 are opposite rays.
.A .C .B
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
11. • Collinear points are points that are on the
same line.
• Coplanar points are points that lie in the same
plane.
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
12. Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
13. • Two different lines intersect in one point.
• Two different planes intersect in one line.
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.
14. Example: Sketch two planes that
intersect in a line.
Essential Question: How do you name geometric figures?
Demonstrated in writing on summary at the end of notes.