Let us calculate by which positive smallest number should be divided with the numbers below so that the quotient will be a perfect cube.
i. 7000 ii. 2662
iii. 4394 iv. 6750
v. 675
Let us recall what a perfect cube is.
A perfect cube is a number that is the cube of an integer.
(i). For 7000.
We need to factorize 7000. We get,
7000 = 7 × 2 × 5 × 2 × 5 × 2 × 5
Group these factors into three similar integers.
7000 = (2 × 2 × 2) × (5 × 5 × 5) × 7
To make it into perfect cube, divide it by 7 on both sides.
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⇒ 1000 = (2 × 2 × 2) × (5 × 5 × 5)
Since, we are able to group it in three similar integers. This means, 1000 is a perfect cube.
Thus, smallest positive number that should be divided with 7000 is 7.
(ii). For 2662.
We need to factorize 2662. We get,
2662 = 2 × 11 × 11 × 11
Group these factors into three similar integers.
2662 = (11 × 11 × 11) × 2
To make it into perfect cube, divide it by 2 on both sides.
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⇒ 1331 = (11 × 11 × 11)
Since, we are able to group it in three similar integers. This means, 1331 is a perfect cube.
Thus, smallest positive number that should be divided with 2662 is 2.
(iii). For 4394.
We need to factorize 4394. We get,
4394 = 2 × 13 × 13 × 13
Group these factors into three similar integers.
4394 = (13 × 13 × 13) × 2
To make it into perfect cube, divide it by 2 on both sides.
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⇒ 2197 = (13 × 13 × 13)
Since, we are able to group it in three similar integers. This means, 2197 is a perfect cube.
Thus, smallest positive number that should be divided with 4394 is 2.
(iv). For 6750.
We need to factorize 6750. We get,
6750 = 5 × 5 × 5 × 3 × 3 × 3 × 2
Group these factors into three similar integers.
6750 = (5 × 5 × 5) × (3 × 3 × 3) × 2
To make it into perfect cube, divide it by 2 on both sides.
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⇒ 3375 = (5 × 5 × 5) × (3 × 3 × 3)
Since, we are able to group it in three similar integers. This means, 3375 is a perfect cube.
Thus, smallest positive number that should be divided with 6750 is 2.
(v). For 675.
We need to factorize 675. We get,
675 = 5 × 5 × 3 × 3 × 3
Group these factors into three similar integers.
675 = (3 × 3 × 3) × 5 × 5
To make it into perfect cube, divide it by (5 × 5) on both sides.
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⇒ 27 = (3 × 3 × 3)
Since, we are able to group it in three similar integers. This means, 27 is a perfect cube.
Thus, smallest positive number that should be divided with 675 is (5 × 5), i.e., 25.
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