Learn about linear pairs of angles with this helpful reference tool. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.

Intermath Dictionary's site defines terms relating to angles, gives examples, and offers interactive exercises.

The dynamics of shape in art and the relationship of shape with the other elements of art. The effects of angles and lines on perception.

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.