9514 1404 393
Answer:
(d) √25
Explanation:
The square root of an integer is a rational number if it is the root of a perfect square. From your knowledge of multiplication tables, you know that 25 = 5×5 is a perfect square.
√25 = 5 is a rational number
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Additional comment
It can be useful to memorize the squares of integers up to about 20. You probably already know the first 10 or 12 from your memorization of multiplication tables.
1² = 1, 2² = 4, 3² = 9, 4² = 16, 5² = 25, 6² = 36, 7² = 49, 8² = 64, 9² = 81,
10² = 100, 11² = 121, 12² = 144, 13² = 169, 14² = 196, 15² = 225, 16² = 256,
17² = 289, 18² = 324, 19² = 361, 20² = 400