Triangles Covering Triangles

The following pictures show n unit equilateral triangles covering the largest known equilateral triangles (of side length s).

1. 3. 4.
s = 1
Trivial. s = 3/2 = 1.5
Trivial. s = 2
Trivial.

6. 7. 8.
s =7/3 = 2.333+
Found by David Cantrell in August 2002. s = 5/2 = 2.5
Found by Erich Friedman in 1999. s = 8/3 = 2.666+
Found by David Cantrell in August 2002.

9. 11. 12.
s = 3
Trivial. s = 13/4 = 3.25
Found by Erich Friedman in 1999. s = 10/3 = 3.333+
Found by Erich Friedman in 1999.

13. 14. 15.
s = 7/2 = 3.5
Found by Erich Friedman in 1999. s = 11/3 = 3.666+
Found by David Cantrell in August 2002. s = 15/4 = 3.75
Found by Erich Friedman in 1999.

6.		7.		8.
s =7/3 = 2.333+ Found by David Cantrell in August 2002.		s = 5/2 = 2.5 Found by Erich Friedman in 1999.		s = 8/3 = 2.666+ Found by David Cantrell in August 2002.

9.		11.		12.
s = 3 Trivial.		s = 13/4 = 3.25 Found by Erich Friedman in 1999.		s = 10/3 = 3.333+ Found by Erich Friedman in 1999.

13.		14.		15.
s = 7/2 = 3.5 Found by Erich Friedman in 1999.		s = 11/3 = 3.666+ Found by David Cantrell in August 2002.		s = 15/4 = 3.75 Found by Erich Friedman in 1999.