Ex 6.1, 3 (i) - Chapter 6 Class 8 Cubes and Cube Roots

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Ex 6.1, 3 Find the smallest number by which each of the following numbers must be divided to obtain a perfect cube. (i) 81 We see that 81 = 3 × 3 × 3 × 3 Since 3 does not occur in triplets, ∴ 81 is not a perfect cube. So, we divide by 3 to make triplet So, our number becomes 81 × 𝟏/𝟑 = 3 × 3 × 3 × 3 × 𝟏/𝟑 = 3 × 3 × 3 Now, it becomes a perfect cube. So, we divide 81 by 3 to make it a perfect cube