Provides examples and a video lesson that illustrates parallel and perpendicular lines.

This site from the University of North Caroline at Wilmington provides great information on the lines in a plane. The information that is given is in-depth and complete, touching on the slope of a line, equations of lines, and linear...

In this task, students are shown three unit squares and two line segments connecting two pairs of vertices. They are asked to find the area of a triangle formed by intersecting lines. They can solve it using coordinate geometry or...