Click on a spirolateral in one of these galleries to display a full-size version; see a self-running demonstration of a variety of spirolaterals, or generate one of your own and see all the reversals. "The Art of...

This lesson from Illuminations focuses on quadrilaterals. Students will start with the diagonals of a shape and then deduce the type of quadrilateral that surrounds them. An interactive applet is included that will help...

This geometry lesson from Illuminations examines regular polygons. Students will study reflections using hinged mirrors and examine the interior angles of regular polygons. The lesson allows students to look at the...

Using the real world example of security cameras, this lesson has students explore properties of polygons. Using this example, students will be able to discover a formula as related to polygons. An activity sheet and...