needa know which one is irrational

Answer:
√2
Step-by-step explanation:
For a number to be "irrational", you cannot turn it into a fraction.
2 = 2/1
√4 = 2/1
2^2=4/1
√2 = 1.41421356237
See which one is not a fraction?
That would be your answer because it is irrational