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.
Cuemath
Cuemath: Perpendicular Bisectors
Provides a definition and examples of perpendicular bisectors.
Khan Academy
Khan Academy: Parallel & Perpendicular Lines From Graph
Given points that two lines go through or the graph of each line, classify the lines as parallel, perpendicular, or neither.
CK-12 Foundation
Ck 12: Interactive Geometry: 10.4 Slope of Parallel and Perpendicular Lines
Understand how to find the slope of parallel and perpendicular lines.
CK-12 Foundation
Ck 12: Interactive Geometry: 5.3 Parallel and Perpendicular Line Constructions
Understand the step-by-step processes used to create accurate geometric figures.
Geometry Help
Geometry Help: What Are Perpendicular Lines in Geometry?
Explains the basic concept of perpendicular lines with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
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.
Free Math Help
Free Math Help: Geometry Vocabulary
The tutorial examines basic geometry vocabulary. Definitions and examples of a point, line, line segment, ray, and plane are included.
Wolfram Research
Wolfram Math World: Perpendicular Lines
This site explains what perpendicular means geometricly in mathematics, gives reference to orthoginality, and explains notation for perpendicular segments or lines.
ClassFlow
Class Flow: Parallel and Perpendicular Lines
[Free Registration/Login Required] This flipchart defines and gives opportunities to work with parallel and perpendicular lines. Prentice-Hall, bsee, Parallel, Perpendicular, 5.8, Algebra.
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.
Free Math Help
Free Math Help: Defined Terms
The lesson discusses commonly used geometric terms. Definitions and examples of a line segment, ray, and angle are included.
Free Math Help
Free Math Help: Parallel Lines
The Geometry session explores parallel lines. Properties, definitions, and examples are included.
ClassFlow
Class Flow: Parallel Lines and Angle Relationships
[Free Registration/Login Required] Explore the relationships between parallel lines and the rules of angle measurements.
ClassFlow
Class Flow: Parallel Lines and Planes
[Free Registration/Login Required] This flipchart defines parallel lines and planes. It defines a transversal, the concept of alternate angles, and vertical angles.
Shmoop University
Shmoop: Basic Geometry: Parallel Lines & Transversals
The geometry resource explores parallel lines and transversals. Descriptions, examples, and practice exercises are included.
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.
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.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Perpendicular and Parallel Lines
Find a quick, concise explanation of what perpendicular lines are. An example is given and clearly explained. Also, parallel lines are explained.
Integrated Publishing
Plane Figures
This site describes lines and angles "as found in various plane (flat) geometric figures.".
University of Georgia
University of Georgia: Inter Math: Perpendicular Lines
This site from InterMath opens with a very simple definition of perpendicular lines and has links to challenging problems, more information, related terms and everyday examples of perpendicular lines.
National Council of Teachers of Mathematics
The Math Forum: Math to Build On: Crossing & Parallel Lines
A definition of parallel lines that draws a comparison to planes and provides drawings for examples.