(i) 2.040040004…
An irrational number. It is a non-terminating and non-repeating decimal.
(ii) 1.535335333…
An irrational number. A non-terminating and non-repeating decimal.
(iii) 3.121221222…
An irrational number. A non-terminating and non-repeating decimal.
(iv) \(\sqrt{21}\)
An irrational number.
21 = 3 × 7 is an irrational number. And 3 and 7 are prime and irrational numbers.
(v) \(3\sqrt3\)
An irrational number.
3 is a prime number. So, 3 is an irrational number.
