The problem: 

> 
> One point of the square - $(2,5)$, and lines $x=1$, $x=6$ are given (1 point of the square is on each given line), all points of the square are in the first quadrant.  
> 
>  A square needs to be constructed with this information.
> 
> 
> 

How would you solve this problem and thus determine if a square can even be constructed?  

I'm interested more in your thought process than the solution.  

How do you approach a problem like this?  

Which steps do you take and why?

I've considered equating the distances between points (2,5) and (1, a) with the distance between (2,5) and (6,b).I don't think that anything can be done with this, maybe I have to find something else and make a system of equations?I've tried to find the distance between points (1, a) and (6,b) - that would be equal to sqrt(2)\*n (n is the length of square's side), connect it with some distance (between the given and unknown point) but I can't extract one variable so I can insert it into the first equation.