A 3D geometry proof with few words courtesy of Fawn Nguyen

Fawn Nguyen is so great at sharing interesting math problems.  On twitter, on her blog, in person, and probably some bat signal type thing if you live in California – she’s got such a great nose for interesting math.   By super happy coincidence earlier in the week we were working through oddly similar problems.  I wrote about it here:

When My Evening was Similar to Fawn Nguyen’s Evening

This morning I finally got around to doing a quick version of the problem Fawn shared with my kids.

The problem is this: how do you find the volume of a Rhombic Dodecahedron, or as she put it on Twitter:

Here’s the start, just showing what the shape looks like:

Up next is this fun observation from Fawn:

The final step is figuring out the volume of all of those pyramids – you must must must need a formula, after all, this is math we are talking about, right 🙂

I wish I’d been filming the construction of the pyramids inside of the cube, because my younger son’s face when he realized that the 6 pyramids filled the cube was priceless.

A super fun project that actually can be modified to fill a long time or shorter time.  Really thankful that Fawn shared this one

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