This set of Class 8 Maths Chapter 6 Multiple Choice Questions & Answers (MCQs) focuses on “Square Root”.

1. If we are given the area of a square and we need to find the length of one side, what operation should we carry?

a) Square

b) Cube

c) Take Square root

d) Take Cube root

View Answer

Explanation: The formula of area of a square,

Area=(side)

^{2}

So, in order to find the side where area is given we take square roots on both the sides. Therefore square root would be the right answer and the other options would be incorrect.

2. If area of a square is 144 cm^{2}, then what is the side?

a) 12 cm

b) \(\sqrt{144}\) m

c) 12 m

d) \(\sqrt{144}\) mm

View Answer

Explanation: The formula of area of a square,

Area=(side)

^{2}

So, in order to find the side where area is given we take square roots on both the sides.

Here, 144=x

^{2}

∴x=12 cm.

3. While taking square roots we cannot include _____ numbers.

a) prime

b) natural

c) whole

d) negative

View Answer

Explanation: While taking square roots we have to take care that we cannot have real roots for negative numbers. The roots of negative numbers are imaginary. Hence the correct option would be negative and the others are wrong.

4. What is the square root of 4?

a) -2

b) -3

c) 4

d) -4

View Answer

Explanation: Here when we calculate the root of 4 we get two values, they are 2 & -2. We have only one of the roots as the answer. So, -2 would be the correct answer and others would be incorrect.

5. There are always two real roots of any number.

a) True

b) False

View Answer

Explanation: Yes, there are more than two roots for every number but only two of them can be real others belong to the imaginary category. Therefore the given statement is true.

6. What are the prime factors of 16?

a) 2×4×2

b) 2×2×2×2

c) 8×2

d) 16×1

View Answer

Explanation: Prime factors are the multiplication of all the prime numbers in order to receive the desired number at the end. Here we have the number to be factorized as 16=2

^{4}(i.e.2×2×2×2). Therefore the answer would 2

^{4}(i.e.2×2×2×2).

7. 324= _____________

a) 2×2×9×9

b) 2^{2}×3^{4}

c) 4×3×27

d) 12×27

View Answer

Explanation: Prime factors are the multiplication of all the prime numbers in order to receive the desired number at the end. The prime factors of 324 are 2×2×3×3×3×3 (i.e.2

^{2}×3

^{4}). Therefore the answer would be 2×2×3×3×3×3 (i.e.2

^{2}×3

^{4}).

8. What would be the square root of 961?

a) 31

b) 32

c) 39

d) 36

View Answer

Explanation: Since the square is ending with 1 its root has to end with either 1 or 9. So two options are ruled out and the other two are 31 & 39. When we calculate the square root we find that the square root of 961 is 31. Hence 31 is the correct answer and all others are incorrect.

9. These 2×3×7 are prime factors of some number, find the square of that particular number.

a) 1764

b) 1664

c) 1864

d) 1964

View Answer

Explanation: 2 × 3 × 7 = 42. Now we need to find 42

^{2}. When we add first 42 odd numbers we get, 1764. Therefore the correct answer is 1764 and the others are incorrect.

10. \(\sqrt{361}\) = ______

a) 21

b) 19

c) 11

d) 29

View Answer

Explanation: If we need to find the square root of number 361 we can subtract first 19 odd numbers which would give us 0. From this we can could that 19=\(\sqrt{361}\). Hence 19 is the correct answer and the others are incorrect.

**Sanfoundry Global Education & Learning Series – Mathematics – Class 8**.

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