Naming Points, Lines, and Planes in the Real World

Points, Lines, Planes

Undefined Terms

In geometry the words, Point, Line and Plane are undefined terms. That means that these words do not have a definition, but there is an agreement about what they mean.

Point

A point has NO dimension and is represented by a dot.

Point B, E, C, D are all points on this plane

Line

A line has ONE dimension and is represented by a line with two arrowheads. It extends infinitely in each direction.

Through any TWO points there is exactly ONE line.

You can use any TWO points to name a line.

Line AB, Line CD, Line BE

Plane

A plane has TWO dimensions and is represented by a shape that looks like a floor or a wall.

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. (non-coplanar)

Multiple Choice

In Math this is called a...?

• Ray

• Plane

• Point

• Line

Multiple Choice

In Math this is called a...?

• Line

• Point

• Plane

Multiple Choice

In math these are called...?

• Points

• Lines

• Planes

• Rays

Multiple Choice

Points, Lines, and Planes are all considered What?

• Defined Terms

• Formal Terms

• Undefined Terms

Multiple Choice

Which one of these is NOT a line in this image

• Line: NO

• Line: PQ

• Line NP

Open Ended

Give a name to this plane (hint: you should be using multiple points or just one letter?)

Multiple Choice

What is NOT a name for this Plane?

• Plane R

• Plane: BC

• Plane: JUB