# Are parallel lines equal to each other?

**Parallel lines**are coplanar

**lines**(in the same plane) that never intersect (never cross

**each other**). Since

**parallel lines**have the same steepness, they have the same slope. Non-vertical

**parallel lines**have the same slopes! The slopes are

**equal**.

Consequently, are parallel lines equal?

are **equal** in measure. If two **parallel lines** are cut by a transversal, the alternate exterior angles are congruent. If two **lines** are cut by a transversal and the alternate exterior angles are congruent, the **lines are parallel**.

**other**words,

**the**slopes of

**parallel lines**are equal. Note that two

**lines are parallel**if their slopes are equal and they have

**different**y-intercepts. In

**other**words, perpendicular slopes are negative reciprocals of

**each other**. Here is a quick review of

**the**slope/intercept form of a

**line**.

Also to know, are parallel lines equal in length?

The angles that fall on the same sides of a transversal and between the parallels (called corresponding angles) are **equal**. The two parallels **lines** are a constant distance apart, so any pair of **lines** that intersects them at the same angle will make segments with the same **length**.

**Parallel Lines** & **Transversals**. A **transversal** is a **line**, or **line** segment, that intersects two or more other **lines**, or **line** segments. When a **transversal** intersects **parallel lines**, many angles are congruent.