## 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} = 6^{3}

**(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