Geometry
posted by Alessio .
Hi, one Professor gave me a very hard question, He has a little Disk (used in machines) that has a big hole in the middle, he measured the thickness every 90°, and he got the following measurements:
0.95 mm
1.02 mm
1.02 mm
0.96 mm
He tells me that with 3 of these measurements, I can know which is the maximum thickness and the minimum thickness even though he didn't measure the thickness everywhere, he wants to know the maximum and minimum thickness to know if the Disk has a big slope and may fail in the machine.
I would be really happy if you could help me with this one :)

I believe you have posted this question before. The reason you may not have got an answer, as far as I am concerned, is that the question is not complete. Perhaps your teacher did not provide the information because it was obvious for him.
For anyone to be able to calculate/predict the fourth thickness, or even the thickness at any point around the circumference, we need to know the "function" that governs the thickness. It could be a sine or cosine variation, or it could be anything else.
Given only 3 or four thicknesses on the circumference, we could fit an infinite number of functions and so calculate an an uncountable number of answers.
If I have misinterpreted your question, let me know. 
I too have seen this post several times, and as PC stated above, was not able to follow the problem as stated.