A tetrahedron is a three-dimensional shape with four triangular faces, six edges, and four vertices. To calculate the volume of a tetrahedron, you can use the formula: V = \frac13 \times \textBase Area \times \textHeight . The base can be any of the triangular faces, and the height is the perpendicular distance from the base to the opposite vertex. Alternatively, if you know the lengths of all four vertices, the volume can be calculated using the formula: V = \frac16 | \veca \cdot (\vecb \times \vecc) | , where \veca, \vecb, and \vecc are vectors representing the edges of the tetrahedron. This method is useful in more complex geometric problems.