Question

underroot 21 is rational or not

Answer 1

Step-by-step explanation:

$\sqrt{21}$

is an irrational number because 21 is not a perfect square and any number, if is not a perfect square, then that number under square root is always an irrational number.

FOR EXAMPLE:

$\sqrt{9} = 3$ , so it is a rational number.

But,

$\sqrt{12} = 2 \sqrt{3}$ , so it is an irrational number.

Answer 2

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√21 is an irrational number because 21 is not a perfect square and any number, if is not a perfect square, then that number under square root is always an irrational number.