Question 1106219
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From Wikipedia:


<pre>
    In geometry, an octahedron (plural: octahedra) is a polyhedron with eight faces, twelve edges, and six vertices. 
    The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, 
    four of which meet at each vertex.
</pre>


For the solution, see the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/geometry/Solved-problems-on-volume-of-pyramids.lesson>Solved problems on volume of pyramids</A>

in this site, where the similar problem was solved.