Algebra students need practice determining equations of lines given a pair of points, or the line parallel or perpendicular to a given line through a given point. This Demonstration, along with guiding worksheets or a teacher presentation, gives students a chance to see the relationships between these lines and points.

You can drag the two red points. Click the parallel or perpendicular check boxes to get a third point, which you can also drag. Zoom can be varied to include larger coordinate values.

Special thanks to Dr. Steven Broad, University of Notre Dame, for assistance.