Question

Select all irrational numbers

Answer 1

$\sqrt{9}=3\notin\mathbb{I} \\\sqrt{12}=2\sqrt{3}\in\mathbb{I} \\\sqrt{16}=4\notin\mathbb{I} \\\sqrt{20}=2\sqrt{5}\in\mathbb{I} \\\sqrt{25}=5\notin\mathbb{I}$

Hope this helps.