[MamaSpoldi]

Here is the equation we used last year:

positionDeg = (analogPot->GetAverageVoltage() - INHERENT_ZERO) * VOLTAGE_TO_DEGREES;

where INHERENT_ZERO was a value we measured and defined within our code for the position we chose to view as zero degrees;
and VOLTAGE_TO_DEGREES was a value calculated ahead of time to convert the voltage over a 90 deg travel into degrees. (This is simple to do because it is just a linear conversion. Take the difference of the pot voltage at 0 and at 90 and then divide by 90 to get this value.)

Hope that helps.