RS Aggarwal Class 8 Math Fourth Chapter Cubes and Cube Roots Exercise 4D Solution
EXERCISE 4D
OBJECTIVE QUESTIONS
Tick (√) the correct answer in each of the following:
(1) Which of the following numbers is a perfect cube?
Ans: (C) 216
216 = 2 × 2 × 2 × 3 × 3 × 3 = (2 × 3)3 = 63
(2) Which of the following numbers is a perfect cube?
Ans: (b) 1331
1331 = 11 × 11 × 11 = (11)3
(7) By what least number should 648 be multiplied to get a perfect cube?
Ans: (c) 9
648 = 2 × 2 × 2 × 3 × 3 × 3 × 3.
Clearly, to make it a perfect cube, it must be multiplied by (3 × 3) = 9.
(8) By what least number should 1536 be divided to get a perfect cube?
Ans: (a) 3
1536 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 3.
Clearly, to make it a perfect cube, it must be divided by 3.
(10) (0.8)3 = 0.8 × 0.8 × 0.8 = (c) 0.512
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