The number is irrational, which means those y values in the table are irrational as well. So there's no way to get exact fractions for any of the decimal values.
The next best thing is to get approximate fractions.
A number like 4.1548 is the same as
Then we can say:
Optionally we can reduce that if you wanted.
So the fraction 41548/10000 turns into the decimal 4.1548
The other decimal values are handled in a similar fashion.
I'm not sure why your teacher wants you to work with fractions. It's better if somehow you can type in the coordinate values as they appear in decimal form.