# Square and Cube Roots Quiz Set 014

### Question 1

One-fourth of the square-root of which number is 0.6?

A

5.76.

B

.5.24

C

5.96.

D

5.49.

Soln.
Ans: a

Let the number be n. So \${1/4} × √n\$ = 0.6, which gives \$√n\$ = 4 × 0.6 = 2.4. so n = \$2.4^2\$ = 5.76.

### Question 2

What is √0.0004?

A

0.02.

B

0.4.

C

0.2.

D

0.002.

Soln.
Ans: a

We can see that 0.02 × 0.02 = 0.0004, so square root is 0.02.

### Question 3

What is the value of \$(√5 - 1/√5)^2\$?

A

\$3{1/5}\$.

B

\$3{2/5}\$.

C

\$3{3/5}\$.

D

\$3{4/5}\$.

Soln.
Ans: a

I will give a general solution for any n. \$(√n - 1/√n)^2\$ is same as \$({(√n)^2 - 1}/√n)^2\$ which becomes \$(n - 1)^2/n\$. Putting n = 5, we get \${16/5}\$, which is same as: \$3{1/5}\$.

### Question 4

What is √(480) × √(1080)?

A

720.

B

240.

C

360.

D

120.

Soln.
Ans: a

We can see that √(480) × √(1080) is same as √(2 × 2 × 2 × 2 × 2 × 3 × 5 ) × √(2 × 2 × 2 × 3 × 3 × 3 × 5 ) which equals √(28 × 34 × 52), which equals (24 × 32 × 51), which gives 720.

### Question 5

What is the least number that should be subtracted from 0.0864 to make it a perfect square?

A

0.08.

B

0.07.

C

0.06.

D

0.09.

Soln.
Ans: a

We know that 0.08 = \$√0.0064\$, so by inspection we can see that 0.0864 - 0.08 will give us 0.0064. This Blog Post/Article "Square and Cube Roots Quiz Set 014" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2020-02-07. Published on: 2016-04-20