Question

The smallest number by which 252 must be multiplied so that the resultant is a perfect square is:

• A. 2
• B. 3
• C. 5
• D. 7

Answer 1

The correct option is D 7

The prime factorisation of is:
$252=2\times 2\times 3\times 3\times 7$

Since the prime factors of a square number exist in pairs, 252 must be multiplied by 7 so that the resultant has the three prime factors - 2, 3 and 7 - in pairs.