I think it has to do with geometry and algebra.
We have a rectangle with four points.
- We know each point as $(0,0), (0,10),(10,10)$ and $(10,0)$.
- In the rectangle we have another point $(x,y)$.
- The distance from this point to the other points is known: $a,b,c,d$
How do we figure out $x,y$ of the point?