Points or lines are said to be **coplanar** if they lie in the same plane.

**Example 1:**

The points *P*, *Q*, and *R* lie in the same plane *A*.

They are *coplanar*.

**Example 2:**

The points *P*, *Q* and *R* lie in the plane *A* and the point *S* lies on the plane *B*.

They are *non coplanar*.

**Example 3:**

They are *coplanar*.

**Example 4:**

They are *non coplanar*.