English: How to geometrically find the center of a hyperbola:

1. Take two points, A and B, on the same piece of the hyperbola
2. Take another point, A', on the hyperbola
3. Draw a line through A', parallel to AB
4. Let the other intersection of the new line and the hyperbola be B'
5. Let M be the midpoint of [AB] and M' the midpoint of [A'B']
6. Let I and I' be the intersections of the hyperbola with MM'

7. The center, O, is the midpoint of [II']