Although the files are misspelled, this is one of my favorite programs and was originally created on the TI-81 (this version uses the nav menu feature so its no longer TI-81 friendly). The help button shows you the equation in its standard triangular form as well as the graph/cicle form. Select which variable you wish to solve for and the program will prompt for the other two and then solve for the third (or the one you selected).
