Piano Tuning

Luckily, the mechanics of tuning this keyboard are easy… you just need to work out which frequency to assign to each note…

You try to recollect any relevant info you might have picked up over the years. You allow your eyes to wander up and down the 88 key keyboard…

You realise that you could pick a relatively middling key on the keyboard, and assign to this a relatively middling frequency. You wonder if a graph might help, so you painstakingly draw out the following:

Looking at this graph, you realise that drawing a curve through the points would assign a frequency to each key on the keyboard.

Source: sidsite.com