Packing $10$ unit circles in an equilateral triangle
OwOUwUOwU, via Wikimedia Commons. CC BY-SA 4.0.
The side length of the smallest equilateral triangle into which $10$ unit circles can be packed.
Value: $6+2\sqrt{3}$ (≈9.464102)
Updates
-
Upper bound: $6+2\sqrt{3}$
(≈9.464102)
Reference unknown
[via Circles in Triangles, Erich Friedman] -
1961
Lower bound: $6+2\sqrt{3}$
(≈9.464102)
Oler and Groemer in 1961
[via Circles in Triangles, Erich Friedman]