Learn: Geometry

Point

An exact location in space with no size or dimension.

How to Name a Point

Use one capital letter (e.g., Point A).

Line

A straight path that extends forever in both directions.

How to Name a Line

Use two points on the line or a lowercase script letter.

Plane

A flat surface that extends forever in all directions.

How to Name a Plane

Use three noncollinear points or a script capital letter.

Collinear Points

Points that lie on the same line.

Coplanar Points

Points that lie on the same plane.

Line Segment

Part of a line with two endpoints.

Endpoints

The points at the beginning and end of a line segment.

Ray

Part of a line with one endpoint extending forever in one direction.

Opposite Rays

Two rays with the same endpoint that extend in opposite directions.

Intersection

The point or set of points where geometric figures meet.

Intersection of Two Lines

Forms exactly one point.

Intersection of Two Planes

Forms a line.

Space

The set of all points.

Dimension

A measurement of space in a particular direction.