Set of points, or lines or line segments or rays or geometrical shapes which lie on the same plane are said to be co-planar.

**Coplanar points**In the above diagram, we can see that two planes intersect ( meet ) along a line. The points A and B are on one plane and the points M and N are another plane.

**Therefore, Points A and B are coplanar.**similarly the points M and N are co-planar.

**Coplanar lines**The lines which lie on the same plane are said to be coplanar lines.

In the above figure, we can see that the lines, l, m and n lie on the same plane, hence they are coplanar.

**Coplanar line segments**In the above diagram, the line segments, $\overline{AB}$, $\overline{BC}$, $\overline{CA}$ and $\overline{PQ}$ are on the same plane and hence they are called as

**coplanar line segments**.

**Coplanar rays**In the above figure, the rays $\overrightarrow{OA}$, $\overrightarrow{OB}$, $\overrightarrow{PQ}$ lie on the same plane and hence they are called as

**coplanar rays**.

**Coplanar geometrical shapes**In the above figure, the shapes

**rectangle and rhombus lie on plane 1** and the shapes,

**square and triangle lie on plane 2.****The shapes on the same plane are coplanar.**Therefore, rectangle and the rhombus are coplanar.

similarly the square and the triangle are coplanar.