Sonoma State University
Sonoma State University: Parallel Lines and Similar and Congruent Triangles
This site defines parallel lines, parallel lines cut by a transverse, and congruent triangles. It also contains links for related terms.
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: Parallel and Skew Lines
[Free Registration/Login may be required to access all resource tools.] This concept teaches students about parallel and skew lines.
Texas Instruments
Texas Instruments: Mc Dougal Littell Geometry: Investigate Slopes
Students can use the TI-84 Plus family with Cabri Jr. to investigate properties of parallel lines.
The Math League
The Math League: Basic Terms: Parallel Lines
This tutorial provides an explanation and example of parallel lines.
Texas Instruments
Texas Instruments: Parallel Lines
This file contains questions related to parallel lines cut by a transversal and the angles formed. The questions can be used to asses your students' understanding of this topic in geometry.
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.
Oswego City School District
Regents Exam Prep Center: Geometry Vocabulary Resources
A list of geometry definitions and a matching activity.
Cuemath
Cuemath: Lines
Learn all about lines. This lesson targets what is a line and the different types. Check-out the interactive simulations to know more about the lesson and try your hand at solving a few interesting practice questions at the end of the page.
CK-12 Foundation
Ck 12: Geometry: Proportionality Relationships Study Guide
[Free Registration/Login may be required to access all resource tools.] This study guide looks at proportionality theorems for triangles and parallel lines intersected by transversals.
CK-12 Foundation
Ck 12: Elem Math: Identifying Parallel and Perpendicular Lines
[Free Registration/Login may be required to access all resource tools.] Students practice identifying parallel and perpendicular lines after watching a video tutorial.
CK-12 Foundation
Ck 12: Elem Math: Determining Whether Lines Are Parallel
[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems to determine if lines are parallel.
Math Is Fun
Math Is Fun: Parallel Lines
Students learn about parallel lines and pairs of angles. Definitions and examples are included.
ClassFlow
Class Flow: Parallel Lines and Angles
[Free Registration/Login Required] This flipchart regards parallel lines and relationship of angles created by a transversal. Includes lesson on vocabulary, Jeopardy-style game, and quiz.
ClassFlow
Class Flow: Parallel Lines and Angle Relationships
[Free Registration/Login Required] Explore the relationships between parallel lines and the rules of angle measurements.
Mangahigh
Mangahigh: Shape: Recognize Perpendicular and Parallel Lines
Explore parallel and perpendicular lines on grids.
Math Open Reference
Math Open Reference: Points and Lines
A complete reference guide to points, lines, and planes. It provides definitions and interactive activities that enhance further explanation.
Oswego City School District
Regents Exam Prep Center: Slopes and Equations of Lines
Three resources for teaching slopes and equations of lines: a lesson with a formula for finding slope, different equations for lines, and several examples; a fourteen-question quiz covering slope, perpendicular and parallel lines, and...
Free Math Help
Free Math Help: Parallel Lines
The Geometry session explores parallel lines. Properties, definitions, and examples are included.
Mr. Martini's Classroom
Mr. Martini's Classroom: Basic Geometry: Points, Lines, and Angles
Students can review basic geometric terms using these self-check, multiple choice questions. Three levels of questions are provided.
City University of New York
Lehman College: An Introduction to Lines
Use this site for two short lesson plans regarding Euclidean and Spherical lines. Intersecting and parallel lines are discussed. The lesson contains activities for two days of class.
Mr. Martini's Classroom
Mr. Martini's Classroom: Geometry Special Angle Pairs and Parallel Transversals
Students are challenged to identify and measure angles created by parallel lines and a transversal as well as complementary and supplementary pairs.
CK-12 Foundation
Ck 12: Geometry: Alternate Exterior Angles
[Free Registration/Login may be required to access all resource tools.] Use alternate exterior angles to determine congruency and the presence of parallel lines.
CK-12 Foundation
Ck 12: Geometry: Alternate Interior Angles
[Free Registration/Login may be required to access all resource tools.] Use alternate interior angles to determine angle congruency and the presence of parallel lines.