It’s an irrational number. It cannot be put into the form x/y where x and y are integers.

It’s belongs with irrational numbers as there is no way to express that number except as the square root of 5. No fraction can be used to express it or complete decimal (it goes on forever without a pattern which is characteristic of irrational numbers. Pi is another example of an irrational number). Curious to know, what was your answer?

Ninja’d

They may have wanted a proof that square root of 5 is irrational which isn’t too hard

It’s an irrational number, and it belongs to the set of real numbers.

√(5) ∈ ℝ

Thank you for all the answers. You were very helpful. It’s a lot clearer for me now.
@flutherother thanks for the link.