# Plane

A **plane** has two dimensions: **length and width**.

It is represented by a parallelogram or a quadrilateral.

The angles are named by Greek letters: α (alpha), β (beta) ...

#### A Plane is Determined by:

Three points that are not aligned.

Two lines that intersect.

Two parallel lines.

A point and a line.

## Properties of the Plane

1.A plane contains infinite points.

2.A plane contains infinite straight lines.

3.A plane is unlimited.

4.Two intersecting planes determine a line.

5.A straight line that has two points in the plane is contained in that plain.

6.A straight line passes through infinite planes.

### Half-Plane

A half-plane is each of the parts that a plane is divided into when intersected by a line or another plain.

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