El Paso Community College
Geometry Definitions
Geometry is full of shapes, figures, and corresponding things here and there. The guide shares all of the key pieces of geometric information in a nicely color-coded and labeled sheet.
McGraw Hill
Lines and Angles
Why was the obtuse angle upset? Because it was never right! A valuable resource is loaded with background information on types of angles and lines. Learners review the characteristics of parallel, perpendicular, and...
Geometry Help
Geometry Help: What Are Parallel Lines in Geometry?
Explains the basic concept of parallel lines in Geometry with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Sonoma State University
Sonoma State University: Parallel Lines and Similar and Congruent Triangles
This site defines eleven theorems relating to parallel lines and similar and congruent triangles. Links to the theorems and relevant term descriptions are provided.
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.
The Math League
The Math League: Basic Terms: Parallel Lines
This tutorial provides an explanation and example of parallel lines.
Oswego City School District
Regents Exam Prep Center: Geometry Vocabulary Resources
A list of geometry definitions and a matching activity.
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: 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.
CK-12 Foundation
Ck 12: Geometry: Angles and Transversals Study Guide
This study guide on angles and transversals covers key terms, angle types formed by transversals, postulates and theorems about transversals, and how to prove if lines are parallel or perpendicular. It is available for download with free...
Geometry Help
Geometry Help: Lines and Angles
Explains the basic concept of lines and angles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
CK-12 Foundation
Ck 12: Geometry: Lines in the Coordinate Plane Study Guide
This study guide on lines in a coordinate plane covers key terms, what different line slopes look like, postulates about parallel and perpendicular lines, the slope-intercept equation, how to graph parallel and perpendicular lines, and...
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.
Purple Math
Purplemath: Conventions
A "convention" is "just the way a thing is done!". This reference material lists some common conventions (notational assumptions) for geometry and trigonometry.