Check whether $7 \sqrt{5}, \,\frac{7}{\sqrt{5}}, \,\sqrt{2}+21, \,\pi-2$ are irrational numbers or not.
Check whether $7 \sqrt{5}, \,\frac{7}{\sqrt{5}}, \,\sqrt{2}+21, \,\pi-2$ are irrational numbers or not.
$\sqrt{5}=2.236 \ldots, \sqrt{2}=1.4142 \ldots, \pi=3.1415 \ldots$
Then $7 \sqrt{5}=15.652 \ldots, \frac{7}{\sqrt{5}}=\frac{7 \sqrt{5}}{\sqrt{5} \sqrt{5}}=\frac{7 \sqrt{5}}{5}=3.1304 \ldots$
$\sqrt{2}+21=22.4142 \ldots, \pi-2=1.1415 \ldots$
All these are non-terminating non-recurring decimals. So, all these are irrational numbers.
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