**ML Aggarwal CBSE Solutions Class 8 Math 4th Chapter Cubes and Cube Roots Exercise 4.1**

**(5)** (i) Volume of cuboid = 3 x 3 x 5

= 45 cm^{3}

Therefore It is not a perfect cube.

We need grouping triplet to form a cube

The perfect cuboid should be = (3 x 3 x5) x (5 x 5 x 3)

(3 x 3 x 3) x (5 x 5 x 5)

∴ (5 x 5 x 3) = 75 cuboid should be needed to form a perfect cube.

(ii) Surface area = 486 cm^{2}

Let side of cuboid box = a

We know that,

6a^{2} = 486

Or, a^{2} = 486/6 = 81

or, a^{2} = 9^{2}

or, a = 9

Therefore side of cuboid box = 9 cm.

**(7)** (i) 125 = 5^{3} => cube of odd number

(ii) 512 = 8^{3} = cube of even number

(iii) 1000 = 10^{3} = cube of even number

(iv) 2197 = 13^{3} = cube of odd number

(v) 4096 = 16^{3} = cube of odd number

(vi) 6856 = 19^{3} = cube of even number

**(8)** (i) 1531 = its cube ends in 1

(ii) 2358 = its cube ends in 2

(iii) 419 = its cube ends in 9

(iv) 4025 = its cube ends in 5

(v) 254 = its cube ends in 4

(vi) 987 = its cube ends in 3

(vii) 6752 = its cube ends in 8

(viii) 93 = its cube ends in 7