OML Search

Pairs Of Lines

In these lessons, we will learn how pairs of lines can relate to each other in four different ways intersecting lines, parallel lines, perpendicular lines, skew lines

These concepts are useful for understanding and solving various geometry problems.

Related Topics:
More lessons on Geometry

Intersecting Lines

Intersecting lines are lines that meet at a point. When two lines intersect, they define angles at the point of intersection.

intersecting lines intersecting lines notation at point C

The following video gives a definition of intersecting lines.

Parallel Lines

Parallel lines are lines that never intersect. The distance between the two lines is fixed and the two lines are going in the same direction.

parallel lines Two parallel lines line notation AB PQ
can be written as parallel line notation
The following video gives a definition of parallel lines.
Parallel lines are coplanar lines that do not intersect.

Perpendicular Lines

Perpendicular lines are lines that intersect at one point and form a 90° angle.

perpendicular lines

Two perpendicular lines line notation AB PQ
can be written as perpendicular line notation

The following video gives a definition of perpendicular lines. Parallel, Perpendicular & Intersecting Lines Song
Song to help you remember what are parallel, perpendicular and intersecting lines.
Parallel lines never meet;
Intersecting lines make v’s;
Perpendicular lines meet at 90 degrees;
Put your hands in the air with me!!

Skew Lines

The above relationships between lines take place on the same plane. However, skew lines only happen in space. Skew lines never intersect because they are not on the same plane. Skew lines are difficult to draw because they exist in the three dimensional space. Lets consider a cube.

skew lines Imagine the lines line notation AB EF running
along the edges of a cube as shown, and line line notation CD running on the front surface of the cube.

They are lines in different planes and will never intersect.

The following video gives a definition of skew lines. Difference between parallel lines and skew lines.
Parallel lines are two coplanar lines that never intersect.
Skew lines are lines that are not coplanar and can never intersect.


Rotate to landscape screen format on a mobile phone or small tablet to use the Mathway widget, a free math problem solver that answers your questions with step-by-step explanations.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

OML Search

We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page.

[?] Subscribe To This Site

follow us in feedly
Add to My Yahoo!
Add to My MSN
Subscribe with Bloglines