Question

Please answer these questions above. Urgent need

Answer 1

Take the LCM of 6,9,15,20
LCM is 180
now prime factorise it and make the doublets. One pair will be so which will be odd let's see:

180=2*2*3*3*5

As we can see that one 5 is also needed to make the no a perfect square. Therefore multiply the no by 5.
180*5=900

Therefore the smallest square no is 900
sq root is 30