Points, Lines, and Planes

1
Points, Lines, and Planes

• Lesson 1.2

2
Definitions

• Point- has no dimensions. Normally represented by
  a dot.
• Line- extends forever in one dimension.
  Represented by a straight line with arrow heads
  on each end.
• Plane- extends forever in two dimensions. Think
  about it as a table top.

3
Definitions

• Collinear Points- points that lie on the same
  line.
• Coplanar Points- points that lie on the same
  plane.

4
Definitions

• Line- extends forever in two directions and
  consists of all points on that line.
• Line Segment- has two endpoints and contains all
  points between the endpoints.
• Ray- has an initial point and extends forever
  through another point and consists of all points
  on that line.

5
Definitions
6
Definition

• Opposite Rays- Two rays with the same initial
  point but run in opposite directions.

7
Example

• Draw three noncollinear points J, K, and L. Then
  draw

8
Example

• Name two pairs of opposite rays.

9
Definition

• Intersect- two geometric figures intersect if
  they have one or more points in common.
• Intersection- the set of points that the
  geometric figures have in common.

10
Intersections

• Two lines intersect at a point.
• Two planes intersect at a line.
• A plane and a line intersect at a point.
• Visuals on page 12.

11
Homework

• pg. 13
• 10-12, 18-20, 25-30, 36-38.