This section of the Project Rho site is one that I have actually used for real projects in the past. The section gives guidelines for creating nomograms, or alignment charts.
Nomograms are graphical representations of a math equation. For a basic 3 variable equation, given 2 of the variables, you simply lay a straight edge across the chart to read the answer from the 3rd scale.
The specific page I linked is a cheatsheet of "standard forms". If you can manipulate your equation into one of these forms, then making it into a nomogram is trivial.
This page is one of very few resources online that will take you step by step through building a nomogram. The intended purpose of the page is to be a resource for board game designers, but I have found it useful in creating time/distance/speed nomograms, various engineering calculations, and calculators for film photography and darkroom printing.
Even if you aren't a math nerd, I hope you find the idea of a graphical representation of an equation as fascinating as I do. It doesn't tell you the answer to 1 question, it tells you the answer to all the questions that an equation can answer simultaneously.