Slime Mold on a Cuboctahedron

Geometry Level 5

A slime mold, in spite of being really just a collection of single cells, is very good at finding the shortest distance between two points, provided they contain food. Researchers put a bit of oatmeal at two opposing vertices of a cuboctahedron with edge size one. The slime mold's job, and yours, is to find the minimal distance along the surface of the solid between these points. If there is more than one such path, multiply this distance by the number of these paths and report the result to 4 decimal places.

Paths which may be derived from each other by rotation or reflection are considered distinct.


Image credit: Wikimedia POV-Ray .


The answer is 16.3923.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Marta Reece
Feb 8, 2017

There are two types of paths, as shown both above.

Distance A D AD can be obtained easily from the two triangles and the square and is 1 + 3 1+\sqrt{3} . The quadrilaterals A B C D ABCD and G F E D GFED are congruent. (They contain three unit sides with the angles between them each made up of one 6 0 60^\circ and one 9 0 90^\circ making them 15 0 150^\circ ). So the distances A D AD and D G DG must be equal.

There are two paths of the type A D AD and four paths of the type D G DG , so the final answer is 6 × ( 1 + 3 ) 6\times(1+\sqrt{3})

It's curious and not immediately obvious that two different paths would have exactly the same distance, but you've given an quick explanation why.

Michael Mendrin - 4 years, 4 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...