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Which of the following is a perfect square?
A50
B81
C160
D250
Answer & Solution
Correct answer: B. 81
81 = 9 × 9 = 9², a perfect square. None of the others can be written as the square of a natural number (50 ≈ 7.07², 160 ≈ 12.65², 250 ≈ 15.81²).
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