[] , [] , [^] , []Circumcenter / Special case (2)(GC World : Various Problems ,Five centroids of triangle etc.)
There are three triagnles (DBA, DBC, DCA) inside of a triagnle.
(1)Where should point D be to make one isosceles triangle?
(2)Where should point D be to make two isosceles triangles?
(3)Where should point D be to make three isosceles triangles?

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Forum of Geometric Constructor by Y.Iijima