Shmoop University
Shmoop: Basic Algebra: Graphing Horizontal and Vertical Lines
The tutorial discusses horizontal and vertical lines. Learners explore the concepts through notes and examples.
Other
Art Education: Drawing in One Point Perspective
A fascinating interactive site showing how to use lines in on-point perspective drawings.
Other
Math N Stuff: Horizontal Lines Constant Functions
This site gives information regarding horizontal lines. The site contains a graph and poses a question relating to the equation of the line on the graph. The correct answer may be clicked on with a short reason.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Equation of a Line Parallel to an Axis
Dr. Math gives a short discussion on how to find the equation of a line parallel to an axis (, parallel or horizontal.)
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: When Is a Slope 0 or Undefined?
At this site Dr. Math gives a discussion on the slopes of lines. The Dr. gives an analogy between the slope of a line and walking up and down hills. The Dr. explores the concept of undefined and zero slopes through his response to a...