No, 180 is not a perfect square! Neither is 2(180)= 360 nor 3(180)= 540, nor 4(180)= 720 but 5(180)= 900 is!

The point of this problem is that because 180 is theleastcommon multiple, any common multiple of the numbers must be a multiple of 180- and 900 is the smallestmultiple of 180 that is a perfect square.

A more efficient method of finding that would be to note that 180= 9(20)= 9(4)(5). 9 and 4 are already "perfect squares". To get a perfect square, you need to multiply by 5: 9(4)(25)= 900.