During the day I was just playing around with the triangles and found a couple of other fun ideas from geometry to show the kids.

First, an alternate proof that the two shapes have the same area. Almost a proof without words! It comes from the fact that the two shapes can come together to form a 6-8-10 triangle:

The next geometric idea involved a right triangle being inscribed in a circle:

It was a really nice surprise that there were other fun (and important!) geometric ideas that our shapes could be used for. We’ve used 3d printing before to play with 2d geometry – including triangles: