Triangles Calculation System

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Version 3.0. New version for mobile devices.
27.6.2009: The program available in German language also.
8.5.2009: New version 2.5. The new element z = alpha - beta has been supplemented. It represents about 120 new combinations of the elements.
25.1.2008: Version 2.0. The program is completely rewritten in Java language. Program start from the web page without instalation is allowed. Localization is automatically chosen according to the system langugage.
15.8.2005: Program is completed with graphs for all combinations.
5.6.2005: The source code is provided with comments on calculation technique.
21.12.2004: The new version adds ability to draw the triangle and all its elements.

Basic information

This program is a general solver for triangles. It computes all possible solutions for a triangle that is specified by an arbitrary triple of the following elements: sides, angles, altitudes, medians, angle bisectors, area, radius of circumscribed and inscribed circle, sum a+b, perimeter and difference of alpha-beta. As a result you obtain all solutions for sides a,b,c. If you mark any solution and click the button Complete, you receive the values of all 21 elements of the given solution. Using the Display button you can draw calculated triangle including choosen elements. By means of the Graph button you open a picture of the graph for given combination. The buttons Display and Graph are not available in a version for mobile phones. The source code is annotated on calculation procedures. Detailed instructions are mentioned in the program under the button Help.
The program is suitable for teachers and students for checking of assigned tasks, and for design engineers and designers. The use is limited only by GPL v3 license.
The program can run on any browser with Java support, on computers with OS Windows, Mac OS/X and Linux and mobile phones supporting Java ME.

input complete
drawing graph
choice mobil input mobil complete mobil

Download (version 3.0)

Download for computer (tar.gz) Download for computer (zip)
The program requires JRE (recommended version 6), which can be free downloaded here.
Download for mobile devices (jar) Download for mobile devices (jad)
Source code (tar.gz) Source code (zip)

About author

My original profession is a designer of special purpose machines, I retired 19 years ago. Mathematics is only one of my hobbies besides philosophy, music, nature and branched family (10 grandchildern). Concerning the general triangle I was at first interested in finding of algorithm for individual assignments. Not until later I worked out the program at first in QBasic, then in Object Pascal in Kylix and Delphi and finally in the language Java SE and Java ME in NetBeans. Because I am not an educated mathematician, it is possible that some procedures and terms are not conform to official mathematical practices. Nevertheless, I tried to write the program very carefully including verification by drawing, and in all more complicated cases I made the computer graph for courses of function for the complete range of possible input. I will appreciate comments and proposals for improvement of the program as well as reminders concerning errors or inaccuracy. Authors E-mail.