Tetrahedron puzzle

Consider a regular tetrahedron with an edge length of 3 units. A regular polyhedron with faces, vertices and edges is made by cutting a regular tetrahedron with an edge length of one unit from each of the 4 corners of the tetrahedron .

Compute .

a. 205
b. 204
c. 209
d. 206
e. 203

Solution

Chop off four little tetrahedrons from the big tetrahedron. The resulting object will now have faces, corners or as they say in mathematics, vertices, and edges.

If you plug these number in to the formula you get
.

And by the way do you know who came up with this formula? It is one of Leonard Euler‘s, one of the most prolific mathematicians of all time.