Question

Which of these numbers is irrational? a)2.3 b)sqrt 3 c)sqrt 4 d)1/3

Answer 1

B it is a surd and surds are irrational

Answer 2

The square root of 3 (b). The reason why is because it cannot be shown as the ratio of two numbers.
You can find out more here: https://www.khanacademy.org/math/algebra/rational-and-irrational-numbers/alg-1-irrational-numbers/v/...