Square Root and Cube Root - General Aptitude

Q1:

The least perfect square, which is divisible by each of 21, 36 and 66 is:

A 213444

B 214344

C 214434

D 231444

ANS:A - 213444

L.C.M. of 21, 36, 66 = 2772. Now, 2772 = 2 x 2 x 3 x 3 x 7 x 11 To make it a perfect square, it must be multiplied by 7 x 11. So, required number = 22 x 32 x 72 x 112 = 213444