Working on the making 7 congruent triangles from the pieces of a triangle dissection question I realized it's possible to do even better! So here it is for extra points:

Use six lines to cut a triangle into nine congruent triangles.

  • $\begingroup$ I assume that, like the other question, we cannot assume anything about the triangle's shape (it is arbitrary)? $\endgroup$ – bobble Aug 30 '20 at 20:10
  • $\begingroup$ this one is easier than others $\endgroup$ – Aakash Mathur Aug 30 '20 at 20:21
  • $\begingroup$ @bobble Yes, arbitrary triangle $\endgroup$ – Kikos Aug 30 '20 at 21:13
  • 3
    $\begingroup$ square numbers are easy. $\endgroup$ – Jasen Aug 30 '20 at 22:14
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    $\begingroup$ Actually, larger number is not always "better" than the smaller number. In this case, the 9 version is apparently (way) more trivial than the 7 version. $\endgroup$ – athin Aug 31 '20 at 1:17


Saves some formatting tokens to not use a spoiler. It's just an image after all.


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