Multiple choice Which of the following decimal numbers is an irrational number? 0.1234569873215.... 0.162162162..... 0.111111111.... 0.545.... Reveal answer Fill a bubble to check yourself A Correct answer Explanation If the decimal expansion of a number is non-terminating and non-repeating, then it is an irrational number. So, 0.1234569873215... is non-terminating and non-repeating, and hence, it is an irrational number.