Does the approach of simply squaring each value hold every time? In other words, 2 times root of 13 squared etc. This way I got values 52, 48, 50 and 54 which helped me to line them up correctly.
Yes, this works, because all the numbers are positive. Obviously, if one or more of the numbers were negative, squaring them would result in positive numbers, which could change the order. But, yes, as it is, with positive numbers, this will always hold.
One other thing - make sure you square both the value inside and outside the root.