Square and Square Roots Class 8 Maths Important Questions

Q 1 – Which of the following is a perfect square number.

(a) 453

(b) 8657

(c) 93542

(d) 729

Q 2 – Which of 225², 97², 53² and 809² would end with digit 1.

(a) 225²

(b) 97²

(c) 53²

(d) 809²

Q 3 – What will be the number of zeros in the square of the number 7000?

(a) 3

(b) 5

(c) 6

(d) 9

Q 4 – How many natural numbers lie between 13² and 14².

(a) 24

(b) 25

(c) 26

(d) 27

Q 5 – Express the square number 5² as the sum of two consecutive integers.

(a) 12 + 13

(b) 10 + 15

(c) 9 + 16

(d) 20 + 5

Q 6 – Which of the following is not a Pythagorean triplet?

(a) 6, 8, 10

(b) 8, 15, 17

(c) 2, 5, 7

(d) 5, 12, 13

Q 7 – What could be the possible one’s digit of the no. whose square is 361?

(a) 3, 4

(b) 6, 7

(c) 1, 9

(d) 7, 8

Q 8 – The smallest number by which 75 should be multiplied so as to get a perfect square is

(a) 2

(b) 3

(c) 5

(d) 7

Q 9 – The number of digits in the square root of 78400 is ………….

(a) 1

(b) 2

(c) 3

(d) 4

Q 10 – Which of the following is the number of non-perfect square number between 17² and 18²?

(a) 613

(b) 35

(c) 70

(d) 34

Q 11 – Fill in the blanks:

  1. 1² = 1 then the square root of 1 is ………………..
  2. 8² = 64 then square root of ……………… = 8.
  3. The number of digits in the square root of 441 is ……………..
  4. The smallest 3-digit perfect square is ………………….
  5. If a number has 4 or 6 in the units place then, its square ends in ………………..

Q 12 – Find the perfect square numbers between 40 and 50.

Q 13 – Write each of the following numbers as difference of the square of two consecutive natural numbers.

(i) 49

(ii) 75

(iii) 125

Q 14 – Find the product of the following:
(i) 23 × 25                 (ii) 41 × 43

Q 15 – Which of the following triplets are Pythagorean? 
(i) (14, 48, 50)                            (ii) (18, 79, 82)

Q 16 – Find the square root of the following using successive subtraction of odd numbers starting from 1.
(i) 169       (ii) 81             (iii) 225

Q 17 – A ladder 10 m long rests against a vertical wall. If the foot of the ladder is 6 m away from the wall and the ladder just reaches the top of the wall, how high is the wall?

Q 18 – The area of a rectangular field whose length is twice its breadth is 2450 m2. Find the perimeter of the field.

Q 19 – What is the least number that must be subtracted from 3793 so as to get a perfect square? Also, find the square root of the number so obtained.

Q 20 – Show that the sum of two consecutive natural numbers is 132.

Q 21 – What would be the square root of 625 using the identity (a + b)2 = a2 + b2 + 2ab?

Q 22 – Find the square roots of 100 and 169 by the method of repeated subtraction.

Q 23 – 2025 plants are to be planted in a garden in such a way that each row contains as many plants as the number of rows. Find the number of rows and the number of plants in each row.