The three points A, B and C define a plane in space.[br]The vectors AB and AC are two vectors that span the plane from the position vector of point A. [br][br]The vector AD is the [b]normal[/b] (perpendicular) to vectors AB and AC. [br][br]Using the normal vector is another way to define a plane (see [b]g[/b]). That is the [b]Cartesian equation[/b] of a plane.

This page is a good starting point to investigate planes in 3D.[br][br]You may start by adjusting the points to match any problem you are investigating.