NCERT Solutions
Class 8 Maths
Squares and Square Roots

Ex.6.3 Q.6
For each of the following numbers, find the smallest whole number by which it should be multiplied so
as to get a perfect square number. Also, find the square root of the square number so obtained:
1. 252
2. 180
3. 1008
4. 2028
5. 1458
6. 768
1. 252 = 2 × 2 × 3 × 3 × 7
Here, prime factor 7 has no pair. Therefore 252 must be multiplied
by 7 to make it a perfect square.
So, 252 × 7 = 1764
and √1764 = 2 × 3 × 7 = 42
2. 180 = 2 × 2 × 3 × 3 × 5
Here, prime factor 5 has no pair. Therefore 180 must be
multiplied by 5 to make it a perfect square.
So, 180 × 5 = 900
And √900 = 2 × 3 × 5 = 30
3. 1008 = 2 × 2 × 2 × 2 × 3 × 3 × 7
Here, prime factor 7 has no pair. Therefore 1008 must be
multiplied by 7 to make it a perfect square.
So, 1008 × 7 = 7056
and √7056 = 2 × 2 × 3 × 7 = 84
4. 2028 = 2 × 2 × 3 × 13 × 13
Here, prime factor 3 has no pair. Therefore 2028 must be
multiplied by 3 to make it a perfect square.
So, 2028 × 3 = 6084
and 6084 = 2 × 2 × 3 × 3 × 13 × 13 = 78
5. 1458 = 2 × 3 × 3 × 3 × 3 × 3 × 3
Here, prime factor 2 has no pair. Therefore 1458 must be
multiplied by 2 to make it a perfect square.
So, 1458 × 2 = 2916
And √2916 = 2 × 3 × 3 × 3 = 54
6. 768 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 3
Here, prime factor 3 has no pair. Therefore 768 must be
multiplied by 3 to make it a perfect square.
So, 768 × 3 = 2304
And 2304 = 2 × 2 × 2 × 2 × 3 = 48
Question 6:
For each of the following numbers, find the smallest whole number by which it should be divided so as to get a perfect square. Also, find the square root of the square number so obtained:
1. 252 2. 2925 3. 396 4. 2645 5. 2800 6. 1620
1. 252 = 2 × 2 × 3 × 3 × 7
Here, prime factor 7 has no pair.
Therefore 252 must be divided by 7 to make it a perfect square.
So, 252 ÷ 7 = 36
And √36 = 2 × 3 = 6
2. 2925 = 3 × 3 × 5 × 5 × 13
Here, prime factor 13 has no pair.
Therefore 2925 must be divided by 13 to make it a perfect square.
So, 2925 ÷ 13 = 225
And √225 = 3 × 5 = 15
3. 396 = 2 × 2 × 3 × 3 × 11
Here, prime factor 11 has no pair.
Therefore 396 must be divided by 11 to make it a perfect square.
So, 396 ÷ 11 = 36
And 36 = 2 × 3 = 6
4. 2645 = 5 × 23 × 23
Here, prime factor 5 has no pair.
Therefore 2645 must be divided by 5 to make it a perfect square.
So, 2645÷ 5 = 529
And √529 = 23 x 23 = 23
5. 2800 = 2 × 2 × 2 × 2 × 5 × 5 × 7
Here, prime factor 7 has no pair. Therefore 2800 must be
divided by 7 to make it a perfect square.
So, 2800 ÷ 7 = 400
And √400 = 2 × 2 × 5 = 20
6. 1620 = 2 × 2 × 3 × 3 × 3 × 3 × 5
Here, prime factor 5 has no pair. Therefore 1620 must be
divided by 5 to make it a perfect square.
So, 1620 ÷ 5 = 324
And 324 = 2 × 3 × 3 = 18