Wolfram Research
Wolfram Math World: Diagonal Matrix
This site gives a definition and examples of a diagonal matrix. The site also contains many links to other related Math World sites.
Texas Instruments
Texas Instruments: Numb3 Rs: Regular Polygon Centroids
Based off of the hit television show NUMB3RS, this lesson shows students different ways to find centroids of regular polygons. The traditional way (using medians) is presented, as well as the triangulation method, the diagonals method,...
Geometry Help
Geometry Help: Squares
Explains the basic concept of a square with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
University of Cambridge
University of Cambridge: Nrich: Diagonal Trace
Develop problem solving skills working with pentagons and then check your results.
Math Open Reference
Math Open Reference: Area of a Kite
A complete reference guide to finding the area of a kite. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
TeachEngineering
Teach Engineering: Determining Densities
Students will use two different methods to determine the densities of a variety of materials and objects. The first method involves direct measurement of the volumes of objects that have simple geometric shapes, while the second uses the...