The tetrahedron is a triangular pyramid with the triangular base having congruent equilateral triangles for each of its faces. The base length of the Pyramid can be found by using the base edge of a triangular pyramid formula. Find the product of apothem length and height of the triangular based pyramid. Then divide the result with 6 times of the volume of the pyramid. The final result gives the base length of the Pyramid. For tetrahedron, there exists a circumsphere on which all four vertices lie.