Geometry · Points, Lines & Angles

Plane

HSG-CO.A.1

Definition

A flat, two-dimensional surface that extends without end in every direction.

Examples

  • Three points that are not on the same line name exactly one plane, Plane P.
  • A tabletop extended infinitely in every direction represents a plane.

Key rule

A plane is perfectly flat and extends infinitely in all directions.

Memory hook

An endless flat sheet.