Question

What is the set of numbers to which `sqrt(82/20)` belong?

Answer 1

Being a radical (root) expression, it would at first belong to the set of irrational numbers.

Explanation:

We could see if things can be taken out from under the radical sign:
`=sqrt((41xxcancel2)/(10xxcancel2))`

But that's about all.

Conclusion:
It is an irrational number, which is a subset of the real numbers.
("irrational" meaning that the number cam't be written as a fraction).