2645 can be factorised as follows. Show
2645 = 5 x 23 x 23 Here, prime factor 5 does not have its pair. If we divide this number by 5, then the number will become a perfect square. Therefore, 2645 has to be divided by 5 to obtain a perfect square. 2645 ÷5 = 529 is a perfect square. 529 = 23 x 23 ∴ `sqrt529` = 23 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. (i) 252 (ii) 2925 (iii) 396 (iv) 2645 (v) 2800 (vi) 1620Solution: We have to find the smallest whole number by which the number should be divided so as to get a perfect square number To get a perfect square, each factor of the given number must be paired. (i) 252 Hence, prime factor 7 does not have its pair. If the number is divided by 7, then the rest of the prime factor will be in pairs. Therefore, 252 has to be divided by 7 to get a perfect square. 252 ÷ 7 = 36 36 is perfect square 36 = 2 × 2 × 3 × 3 = 22 × 32 = (2 × 3)2 Thus, √36 = 2 × 3 = 6 (ii) 2925 Hence, prime factor 13 does not have its pair. If the number is divided by 13, then the rest of the prime factor will be in pairs. Therefore, 2925 has to be divided by 13 to get a perfect square. 2925 ÷ 13 = 225 225 is a perfect square 225 = 5 × 5 × 3 × 3 = 52 × 32 = (5 × 3)2 Thus, √225 = 15 (iii) 396 Hence, prime factor 11 does not have its pair. If the number is divided by 11, then the rest of the prime factor will be in pairs. Therefore, 396 has to be divided by 11 to get a perfect square. 396 ÷ 11 = 36 36 is a perfect square 36 = 3 × 3 × 2 × 2 = 32 × 22 = (3 × 2)2 Thus, √36 = 3 × 2 = 6 (iv) 2645 Hence, prime factor 5 does not have its pair. If the number is divided by 5, then the rest of the prime factor will be in pairs. Therefore, 2645 has to be divided by 5 to get a perfect square. 2645 ÷ 5 = 529 529 is a perfect square 529 = 23 × 23 = 232 Thus, √529 = 23 (v) 2800 Hence, prime factor 7 does not have its pair. If the number is divided by 7, then the rest of the prime factor will be in pairs. Therefore, 2800 has to be divided by 7 to get a perfect square 2800 ÷ 7 = 400 400 is a perfect square 400 = 2 × 2 × 2 × 2 × 5 × 5 = 22 × 22 × 52 = (2 × 3 × 5)2 Thus, √400 = 2 × 2 × 5 = 20 (vi) 1620 Hence, prime factor 5 does not have its pair. If the number is divided by 5, then the rest of the prime factor will be in pairs. Therefore, 1620 has to be divided by 5 to get a perfect square. 1620 ÷ 5 = 324 324 is a perfect square 324 = 2 × 2 × 3 × 3 × 3 × 3 = 22 × 32 × 32 = (2 × 3 × 3)2 Thus, √324 = 2 × 3 × 3 = 18 ☛ Check: NCERT Solutions for Class 8 Maths Chapter 6 Video Solution: 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. (i) 252 (ii) 2925 (iii) 396 (iv) 2645 (v) 2800 (vi) 1620NCERT Solutions for Class 8 Maths Chapter 6 Exercise 6.3 Question 6 Summary: For each of the following numbers (i) 252 (ii) 2925 (iii) 396 (iv) 2645 (v) 2800 (vi) 1620, the smallest whole number by which it should be divided so as to get a perfect square and the square root of the square numbers are as follows (i) 7; √36 = 6 (ii) 13; √225 = 15 (iii) 11; √36 = 6 (iv) 5; √529 = 23 (v) 7; √400 = 20 and (vi) 5; √324 = 18 ☛ Related Questions:
Is the number 2645 a perfect square if not find the smallest number by which 2645 should be divided to get a square number also find the square root of it?If the number is divided by 5, then the rest of the prime factor will be in pairs. Therefore, 2645 has to be divided by 5 to get a perfect square.
What must be added to 2645 to make it a perfect square?Hence, the given number is not a perfect square. Thus, 2645 needs to be divided by 5 to become a perfect square. Thus, the required smallest whole number by which it should be divided so as to get a perfect square number is 5 and the square root is √529= 23.
How do you find smallest number by which is a perfect square?L.C.M. of 8, 15 and 20 is 120. Here, prime factors 2, 3 and 5 have no pair. Therefore 120 must be multiplied by 2 x 3 x 5 to make it a perfect square. Hence, the smallest square number which is divisible by 8, 15 and 20 is 3600.
Is 2601 a perfect square?The square root of 2601 is expressed as √2601 in the radical form and as (2601)½ or (2601)0.5 in the exponent form. The square root of 2601 is 51. It is the positive solution of the equation x2 = 2601. The number 2601 is a perfect square.
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