Dominoes in Circles

The following pictures show n dominoes (with short side 1) packed inside the smallest known circle (with radius r).

1.
           2.
           3.
r = √5/2 = 1.11803+
Trivial. 		r = √2 = 1.41421+
Trivial. 		r = √13/2 = 1.80277+
Trivial.

4.
           5.
           6.
r = 1.97949+
Found by Jonathan Viquerat
in May 2026 		r = 2.18039+
Found by Jonathan Viquerat
in May 2026. 		r = √5 = 2.23607+
Trivial.
 

7.
           8.
           9.
r = 2.51459+
Found by Jonathan Viquerat
in May 2026. 		r = 2.65851+
Found by Jonathan Viquerat
in May 2026. 		r = 2.76860+
Found by Jonathan Viquerat
in May 2026.

10.
           11.
           12.
r = 2.93566+
Found by Jonathan Viquerat
in May 2026. 		r = 3.08826+
Found by Jonathan Viquerat
in May 2026. 		r = √10 = 3.16227+
Found by Maurizio Morandi
in May 2026.

13.
           14.
           15.
r = 3.27852+
Found by Jonathan Viquerat
in May 2026. 		r = 3.37689+
Found by Jonathan Viquerat
in May 2026. 		r = 3.48515+
Found by Jonathan Viquerat
in May 2026.

16.
           17.
           18.
r = √13 = 3.60555+
Found by Jonathan Viquerat
in May 2026. 		r = √53/2 = 3.64005+
Found by Maurizio Morandi
in May 2026. 		r = 3.78121+
Found by Jonathan Viquerat
in May 2026.

19.
           20.
r = 3.89344+
Found by Jonathan Viquerat
in May 2026. 		r = 3.99407+
Found by Jonathan Viquerat
in May 2026.