That was genuinely upsetting to read.

Teacher was like, nah, that's not possible, and clearly hadn't even read it. Gave me an A just to stop me complaining, still not understanding the project.

I didn’t pass because the point of the assignment was to use lookup tables, even though that was a more complex approach in this case :(

Are you sure about easy to calibrate 8) Did your solution have the same level of accuracy across the range as the MCU would provide?

Bizarrely, you sometimes have to follow the standards because that is what everyone does. I can't think of an example now but there will and have been cases in engineering where the wrong answer is the right one because that is what is done. I know of mensuration devices that "model" some curves with a linear approximation and paper over the errors with cough error estimates and/or keeping within the nearly linear range. That too is fine if everyone understands what is going on.

Accuracy is a funny old thing.

However, I like your approach and it shows you probably understand the principles involved. Ideally, if you are going to be a smart arse like that, then submit two solutions - the proscribed one and your clever one.

You mention a MCU but not what sort of sensor ...