1. Lesson 1 – 1 Points, Lines, and Planes
Geometry
Lesson 1 – 1
Points, Lines, and Planes
Objective:
Identify and model points, lines, and planes.
Identify intersecting lines and planes.

2. Undefined terms
Undefined terms: objects that are only explained using examples and descriptions.
Point
Line
Plane

3. Point Point: Named: Example A point is a location.
Has neither shape nor size
Named:
Capital letter
Example
Point A

4. Line Line: Named: Example Made up of points Has no thickness or width
Exactly one line through and two points.
Named:
Any 2 points on the line (2 capital letters)
Lowercase script letter
Example
line m or

5. Plane Plane: Named Example K
A flat surface made up of points that extends infinitely in all directions.
Exactly one plane through any 3 points not on the same line.
Named
Capital Script letter
3 points on the plane not on a line (3 capital letters)
Example K
Plane BCD (any order)

6. Definitions Collinear: Noncollinear: Coplanar Noncoplanar
Points that lie on the same line
Noncollinear:
Points that do not lie on the same line.
Coplanar
Points that lie in the same plane
Noncoplanar
Points that do not line in the same plane

7. Use the figure to name each of the following:
A line containing point W
A plane containing point X
Any one of the following work:
Any one of the following work: (3 letters that are noncollinear)
P, plane XZY, plane VZY, plane VZW,
plane WZX, plane VZX, Plane WZY

8. Example
Name the geometric term modeled by the objects in the picture.
Push pin
Maroon boarder
The card itself
Stripes on a sweater
Corner of a box
Point G
Sample: plane FGJ
lines
point

9. Intersection
Intersection of two or more geometric figures is the set of points they have in common.
Where do two lines intersect?
Where do two planes intersect?
At a point.
At a line

10. Draw the following intersects plane T at point S. Sample answer
Must have the dashed line to show that the line goes through
the plane and is not on or in the plane.

11. Draw the following Line p lies in plane N and contains point L.
Sample answer.

12. Definitions
Definitions are defined terms that are explained using undefined terms and/or other defined terms.
Space: defined as a boundless, three-dimensional set of all points. Space can contain lines and planes.

13. Name 3 points that are collinear.
How many planes appear
in this figure.
Name 3 points that are collinear.
Name the intersection of plane HDG with plane X.
At what point do LM and EF intersect? Explain.
6 planes: 5 around the pyramid and one on
bottom of the the pyramid… don’t name the
bottom plane twice.
Points J, K, and D
Make sure you have commas otherwise it names a plane.
Don’t appear to intersect since L is the only point on
line LM in the plane.

14. No, not all on the same plane.
Are points E, D, F,
and G coplanar?
At what point or in what line do
planes JDH, JDE, and EDF intersect?
No, not all on the same plane.
Point D is the only thing in common.

15. Homework
Pg – 12 all, 14 – 46 EOE, 52, 66 – 82 EOE