Consider a regular tetrahedron with vertices:
(0,0,0) , (k,k,0) , (k,0,k) , and (0,k,k)
a) sketch the graph of the tetrahedron
b) find the length of each edge
c) find the angle between any two edges
d) Find the angle between the line segments from the centroid ( k/2, k/2, k/2) to two vertices.
This provides an example of determining the length and angles in a tetrahedron.