ClassFlow
Class Flow: Discovering Lines
[Free Registration/Login Required] This flipchart defines Parallel, Intersecting, and Perpendicular lines. It also provides opportunities to practice working with Parallel, Intersecting and Perpendicular Lines!
ClassFlow
Class Flow: Lines Parallel
[Free Registration/Login Required] The teacher will use this lesson plan flipchart to review parallel lines.
Other
Derivation and Classification of Groups
This gives examples of classification of the differences between rotation and translation.
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.
Oswego City School District
Regents Exam Prep Center: Parallel Through a Point
This step-by-step demonstration teaches students to construct a line parallel to another through a given point.
Physics Aviary
Physics Aviary: Practice Problems: Parallel Circuit
Determine the amount of current that is present in a parallel circuit.
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.