[ª] , [©] , [^] , [¨]Perpendicular bisectors of four sides of quadrangle / The result is one point(GC World : Various Problems ,Quadrangle¨Quadrangle)
I want to make EFGH into one point.
¥What the shape of ABCD will make EFGH one point?
¥What condition of ABCD will make EFGH one point?

GC/Win


Forum of Geometric Constructor by Y.Iijima