Irrational numbers are:

Question

1-Not fractions
2-Non-terminating and non-repeating decimals
3-Radicals that do not simplify to whole numbers
4-All of the above.

Answer 1

http://www.mathsisfun.com/irrational-numbers.html

Answer 2

1 and 2

3 is false, since √2.25 = 1.5 is a radical that is not a whole number, but is not irrational