# Pappus chain in an ideal triangle of Poincare disk of hyperbolic geometry [closed]

Let IaIbIc be an ideal triangle in Poincare disk.

Denote:

a, b, c = the hyperbolic lines whose ends are Ib and Ic, Ic and Ia, Ia and Ib respectively.

r = the incircle of a, b and c..

A, B, C = the contact points of r and a, b, c respectively.

O = the hyperbolic circumcenter of ABC

r1 = the incircle of r, a and b.

A1, B1, C1 = the contact points of r1 and r, a, b respectively.

O1 = the hyperbolic circumcenter of A1B1C1.

For any ideal triangle, the radius of r = 0.5493061443... = log[3]/2.

The radius of r1 = 0.2554128119...

Questions:

(1)In any ideal triangle, is the radius of r1 the same?

(2)If so, replace the numerical solution of the radius of r1 by the exact one.

(3)We can construct the contact circles ri+1 of ri, a, b for i = 1 to infinity consecutively, compute their radii.

## closed as unclear what you're asking by Lee Mosher, José Carlos Santos, The Count, Shogun, postmortesJun 23 at 5:34

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• It's not clear to me what you are asking. The answers to Questions (1) and (2) are right there printed in your question and in the diagram. – Lee Mosher Jun 20 at 16:08