7629 /www/nrich/html/content/id/7629/ 1 2011-07-15T11:54:55 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> <p>A regular tetrahedron with edges of length 6 cm has each corner cut off to produce the solid shown. The triangular faces are all equilateral triangles, but not necessarily the same size. What is the total length of the edges of the resulting tetrahedron?</p> <p><mdo:image src="tetrahedron.png"></mdo:image></p> If you liked this problem, <a href="http://nrich.maths.org/5673">here is an NRICH task</a> which challenges you to use similar mathematical ideas.<br></br></mdoxml> 2 3 0 0 1 0 0