[ª] , [©] , [^] , [¨]Angle of corner / Confirming (2)(GC World : Various Problems ,Constant)
ÚXAY = 60‹.
Let's change ÚXBY to 60‹.
Where should Point B be placed?
You can use the "Shift" key.

GC/Win

Forum of Geometric Constructor by Y.Iijima