Three Dimensional Figures and Cross Sections
Concept

Coplanar

Any set of points that lie on the same plane are said to be coplanar.
Coplanar points A, B, C, and D lie on a plane, while point E is situated above the plane and is non-coplanar.
In this illustration, and are coplanar, as they are all on the same plane. By contrast, is not on the same plane as the other points, so it is not coplanar with them.
Coplanar and non-coplanar points
Since a plane can be defined by any three points, is still coplanar with other pairs of points. Therefore, there are seven sets of coplanar points on the graph.
Exercises