This is an interactive site that explains the ideas behind trigonometry. It also offers hands on experience in working with triangles.

This geometry lesson from Illuminations introduces a hands-on learning activity for students in grades 9-12. The class will use pasta to create models of triangles. They will examine the relationship between sides and...

Created by Bruce and Katherine Cornwell, this film from 1976 includes no narration but still manages to demonstrate a number of geometric properties of a triangle, including incenter and circumcenter, through simple...

In the introduction to this site we learn that, "A fundamental result of geometry, used often in secondary and collegiate mathematics, is the equality of ratios of corresponding sides in similar triangles." Accordingly,...

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...