This Interactive Web Book explores the geometry behind Heron's formula for the area of a triangle in terms of its sides. The formula may be understood by asking which quadrilateral with assigned side lengths has the largest area. This book has several experiments embedded in its pages, one of which allows the reader to vary the shape of the quadrilaterals to discover the surprising answer, and thereby, to discover Heron's formula.

All of the documentation is available in the book itself as page-by-page HTML Help. Most pages are dynamic interaction pages, where you experiment with the ideas of the story as it unfolds. They offer simulations and command lines that range through topics in geometry, algebra, and single-variable calculus. As you come to each page, open the Help, Help for This Page menu to read (or print) the story, then roll up your sleeves and ... play!

The mathematical documentation for this story was created fairly easily using Design Science MathPage™ technology with Microsoft Word 2000™ and Microsoft Help Compiler. And the mathematical interactions were created with Mathwright32 Author™. The Heron Book may be read in Microsoft Windows™ (95, 98, Me, 2000, or XP) using Internet Explorer Browser 5.0 or later. In order to read it, you should sure you have MathwrightWeb Version 2.10 (after May 12, 2003, or later).

Nearly all of the topics discussed will be accessible to a student who is comfortable with Algebra and Geometry. The crucial step of the argument, however, uses elementary Calculus and may, as a surprising application of the ideas of Limit and Derivative, be taken as a motivation for studying those concepts.

Requires the free Java MathwrightWeb ActiveX Control to read in your Browser.
For proper viewing, be sure to use Version 2.10 or later, dated May 12, 2003
Download free MathwrightWeb to view Microworlds in your browser then press


or

Download and extract the Word 2000 version if you wish to print it (18 pages)

Library members, download the free Mathwright32 Reader, then press

For proper viewing, be sure to use Version 2.10 or later, dated May 12, 2003


Interactive Web Book: Heron's Formula

Click the Hyperlink above to visit the Microworld.
Author: James White

It may appear that the interactions that one finds on the eight exploration pages are simply Java applets. While they behave like applets, they are different from them for several reasons. Perhaps the most important from the viewpoint of authorship and web design is that they were not written in Java, but were created in a high level object-oriented mathematics scripting language called Mathscript. Further the visual design was graphical "point-and-click" or "What you see is what you get." This combination, using our new Mathwright32 Author™ program, produces efficient Java code, but does not require any knowledge of Java itself. It is much simpler to write books with than Java.

One might also point to the range of resources available to this book, and to every interactive web book that uses the MathwrightWeb Control. It uses a symbolic Expert System, computer algebra, sprite animation and graphics, command-line tools, and a special-purpose command language to represent and manipulate geometric objects. All of this is immediately available to the book. An applet would, in principle, have to download these resources each time this book (or a similar book) was read.

Another difference is this. The "microworld" is a multi-page mathematically savvy interactive story that invites you to ask questions, and (usually) gives you answers. You read it with page-by-page HTML Help that provides sophisticated navigation, attractive and colorful mathematical formulas, charts, illustrations and text. It is a new medium. Welcome to the future!

To visit our Interactive Web Books in your browser, it must be able to read ActiveX controls. Microsoft Internet Explorer 4.0 Browser (or later) is so equipped. You should check that the Security Settings under Tools, Internet Options, Security for the Internet, Custom Level has:

  • "Run ActiveX Controls and Plugins" set either to enable or prompt.
  • "Initialize and Script ActiveX Controls not marked as safe" set either to enable or prompt.

Return to the listing of MathwrightWeb Microworlds


    - James E. White, Ph.D. , Library Director,
    author of this website, Mathwright 2000, MindScapes,
    MathwrightWeb, and Mathwright32

 

Mathwright Visualization Studio free demonstration Interactive Web Book:

Heron's Formula