From J. J. O'Connor and E. F. Robertson at the University of St. Andrews in Scotland, this page covers Euclid's Elements through the end of the 1800's, with 23 references (books/articles). Each important name is a link...

Java applets: an area "workshop," which explains area and division by converting numbers in area units; an architect's toy blocks, with gravity; connecting and programming elementary logic (in the form of pipes with...

This geometry lesson from Illuminations asks students to draw two line segments through a point on the diagonal of a parallelogram and parallel to the sides. Students will examine a geometric shape, analyze the patterns...

Plexagon is a new modular geometry based on the radial pleating of polygonal plates, and their joining or co-bracing into 3D modules. This engineering approach can form a very practical basis for modular greenhouses...

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...