The following pictures show n equilateral triangles packed inside a unit pentagon, so that the total sum of the sides of the triangles is as large as possible.
1.
2.
3.
Σ s = cos(18°)/cos(42°) = 1.27977+
Trivial.
Σ s = (1+√5)/√3 = 1.86834+
Trivial
A continuum of solutions.
Σ s = 2.68270+
Found by Jonathan Viquerat
in June 2026.
4.
5.
6.
Σ s = 3.37307+
Found by Jonathan Viquerat
in June 2026.
Σ s = 15/(3+2√3sin(12˚)) = 4.03202+
Found by Jonathan Viquerat
in June 2026.
Σ s = 4.33548+
Found by Jonathan Viquerat
in June 2026.
7.
8.
9.
Σ s = 4.67519+
Found by Jonathan Viquerat
in June 2026.
Σ s = 5.01502+
Found by Jonathan Viquerat
in June 2026.
Σ s = 5.34770+
Found by Jonathan Viquerat
in October 2026.
10.
11.
12.
Σ s = 5.67685+
Found by Pedro Martins
in July 2026.
Σ s = 5.99822+
Found by Jonathan Viquerat
in June 2026.
Σ s = 6.31699+
Found by Joost de Winter
in October 2026.
13.
14.
15.
Σ s = 6.59263+
Found by Pedro Martins
in July 2026.
Σ s = 6.91179+
Found by Pedro Martins
in July 2026.
Σ s = 7.17437+
Found by Jonathan Viquerat
in October 2026.
16.
17.
18.
Σ s = 7.48786+
Found by Jonathan Viquerat
in October 2026.
Σ s = 7.74732+
Found by Jonathan Viquerat
in October 2026.
Σ s = 7.96356+
Found by Jonathan Viquerat
in October 2026.
19.
20.
21.
Σ s = 8.22207+
Found by Joost de Winter
in October 2026.
Σ s = 8.51465+
Found by Pedro Martins
in July 2026.
Σ s = 8.65807+
Found by Jonathan Viquerat
in October 2026.
22.
23.
24.
Σ s = 8.89359+
Found by Jonathan Viquerat
in October 2026.
Σ s = 9.06340+
Found by Jonathan Viquerat
in October 2026.
Σ s = 9.27320+
Found by Joost de Winter
in October 2026.
25.
26.
27.
Σ s = 9.46826+
Found by Jonathan Viquerat
in October 2026.
Σ s = 9.66343+
Found by Pedro Martins
in October 2026.
Σ s = 9.85993+
Found by Pedro Martins
in October 2026.
28.
29.
30.
Σ s = 10.04286+
Found by Pedro Martins
in October 2026.
Σ s = 10.24927+
Found by Pedro Martins
in October 2026.
Σ s = 10.43887+
Found by Joost de Winter
in October 2026.
31.
32.
33.
Σ s = 10.62546+
Found by Pedro Martins
in October 2026.
Σ s = 10.78799+
Found by Pedro Martins
in October 2026.
Σ s = 10.97649+
Found by Pedro Martins
in October 2026.
34.
35.
36.
Σ s = 11.14702+
Found by Pedro Martins
in October 2026.
Σ s = 11.32301+
Found by Joost de Winter
in October 2026.
Σ s = 11.49407+
Found by Joost de Winter
in October 2026.
37.
38.
39.
Σ s = 11.66499+
Found by Pedro Martins
in October 2026.
Σ s = 11.83386+
Found by Pedro Martins
in October 2026.
Σ s = 12.01613+
Found by Pedro Martins
in October 2026.
40.
41.
42.
Σ s = 12.19203+
Found by Joost de Winter
in October 2026.
Σ s = 12.32065+
Found by Joost de Winter
in October 2026.
Σ s = 12.50118+
Found by Pedro Martins
in October 2026.
43.
44.
45.
Σ s = 12.64015+
Found by Pedro Martins
in October 2026.
Σ s = 12.81525+
Found by Pedro Martins
in October 2026.
Σ s = 12.98616+
Found by Joost de Winter
in October 2026.
46.
47.
48.
Σ s = 13.09197+
Found by Pedro Martins
in October 2026.
Σ s = 13.25878+
Found by Joost de Winter
in October 2026.
Σ s = 13.36774+
Found by Joost de Winter
in October 2026.
49.
50.
Σ s = 13.53192+
Found by Pedro Martins
in October 2026.
Σ s = 13.64753+
Found by Pedro Martins
in October 2026.