Which of the following is a perfect square?

1,690Correct answerYour answer2,025Correct answerYour answer2,432Correct answerYour answer2,890Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

$45^2 = 2{,}025$ , so 2,025 is a perfect square.
1,690 and 2,890 end in a single zero; a perfect square ends in an even number of zeros.
2,432 lies between $49^2 = 2{,}401$ and $50^2 = 2{,}500$ .

Worth noting

1,690 contains $169 = 13^2$ , but $1{,}690 = 169 \times 10$ , and 10 is not a square.

Ten questions from Number System, at your own pace.

Ten questions from Number System, at your own pace.

Explanation