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).

pathag

Download TI-85
TI-85 ASCII