Question

For the following number, find the smallest whole number by which it should be divided so as to get a perfect square number. Also find the square root of the square number so obtained.

1620

Answer 1

1620 can be factorised as follows.

2	1620
2	810
3	405
3	135
3	45
3	15
5	5
	1

1620 = 2 × 2 × 3 × 3 × 3 × 3 × 5

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, 1620 has to be divided by 5 to obtain a perfect square.

1620 ÷ 5 = 324 is a perfect square.

324  = 2 × 2 × 3 × 3 × 3 × 3

∴ `sqrt324` =  2 × 3 × 3 = 18