Hi atreyyu,

if you extend the three sides of the triangle such that the triangle sides

are now line segments of these lines, then, there are 3 circles that touch one side of the triangle tangentially

and touch the extended lines tangentially.

If you bisect the appropriate external angle you will have a line whose points are

the same perpendicular distance from the extended line and a side of the triangle.

Do the same for the other relevant extended line and you will find the centre of the circle with centre D (of which there are 3).

That can get you started geometrically.