Wei-Hwa Huang sent this puzzle. "**Divide a square into 7 triangles.
One triangle must have edge lengths in the ratio 3:4:5. The other
6 triangles must be arrangeable into another square!**" He asks
if the same task can be done with less than seven triangles.

Wei-Hwa Huang's Pythagorean challenge has at least 4 solutions with 7 triangles. These were found by Wei-Hwa Huang, Junk Kato, Andrew Cook, and Livio Zucca.

Solution by Andrew Cook (and Junk Kato)