CK-12 Foundation
Ck 12: Parallel and Skew Lines
[Free Registration/Login Required] Students explore the concept of parallel and skew lines by navigating through the interactive learning module and then answering questions that go along with the module. Students can also learn more...
CK-12 Foundation
Ck 12: Geometry: Parallel and Skew Lines
[Free Registration/Login may be required to access all resource tools.] This concept teaches students about parallel and skew lines.
CK-12 Foundation
Ck 12: Geometry: Parallel and Skew Lines
[Free Registration/Login may be required to access all resource tools.] Differentiate between parallel and skew lines.
CK-12 Foundation
Ck 12: Geometry: Lines and Angles Study Guide
This study guide on lines and angles covers key terminology; line notation; parallel, perpendicular, and skew lines; and postulates and theorems about lines. It is available for download with free registration.
Wolfram Research
Wolfram Math World: Parallel Lines
A definition for parallel lines in two-dimensional and three-dimensional Euclidean space. The site also gives reference to skew lines and explains the difference between skew and parallel lines in three-dimensional space.
CK-12 Foundation
Ck 12: Plix: Vision and the Eye: The Line Up
[Free Registration/Login Required] Are your eyes playing tricks on you? This site contains parallel and skew lines that creates an optical illusion.