Question

Which among the following is NOT a perfect square?

• A. $121$
• B. $12,321$
• C. $1,331$
• D. $1,234,321$

Answer 1

The correct option is C $1,331$

$\bullet 121$ can be expressed as:
$121=11\times 11={11}^2$
$\therefore 121$ is a perfect square of $11$.

$\bullet 12,321$ can be expressed as:
$12,321=111\times 111={111}^2$
$\therefore 12,321$ is a perfect square of $111$.

$\bullet 1,234,321$ can be expressed as:
$1,234,321=1,111\times 1,111$
$\therefore 1,234,321$ is a perfect square of $1,111$.

$\bullet 1,331$ can be expressed as:
$1,331=11\times 11\times 11={11}^3$
$\therefore \underset{–}{1,331\text{is NOT a perfect square.}}$

Therefore, option (c.) is the correct answer.