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Find the smallest number by which the given number must be multiplied so that the product is a perfect square: (i) 23805 (ii) 12150 (iii) 7688 |
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Answer» (i) 23805 Resolving 23805 into prime factors, we get 23805 = 3 × 3 × 23 × 23 × 5 Obtained factors can be paired into equal factors except for 5 To pair it equally multiply with 5 23805 × 5 = 3 × 3 × 5 × 5 × 23 × 23 Again, 23805 × 5 = (3× 5 × 23) × (3 × 5 × 23) = 345 × 345 = (345)2 Therefore, product is the square of 345. (ii) 12150 Resolving 12150 into prime factors, we get 12150 = 2 × 2 × 2 × 2 × 3 × 3 × 5 × 5 × 2 Obtained factors can be paired into equal factors except for 2 To pair it equally multiply with 2 12150 × 2 = 2 × 2 × 2 × 2 × 2 × 2 × 5 × 5 × 3 × 3 Again, 12150 × 2 = (5 × 3 × 2 × 2 × 2) × (5 × 3 × 2 × 2 × 2) = 120 × 120 = (120)2 Therefore, product is the square of 120. (iii) 7688 Resolving 7688 into prime factors, we get 7688 = 2 × 2 × 31 × 31 × 2 Obtained factors can be paired into equal factors except for 2 To pair it equally multiply with 2 7688 × 2 = 2 × 2 × 2 × 2 × 31 × 31 Again, 7688 × 2 = (2× 2 × 31) × (2 × 2 × 31) = 124 × 124 = (124)2 Therefore, product is the square of 124. |
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