Concept:A triangular pyramid, also called a tetrahedron, is a solid with a triangular base and three triangular side faces. Its edges are the line segments where two faces meet.Explanation:A triangular pyramid has 4 vertices and 4 faces. The base triangle has 3 edges. The three side faces each add one more edge that meets at the top vertex, giving 3 more edges. So total edges = 3 (base) + 3 (side) = 6. You can also verify: For any pyramid, edges = 2 × (number of sides of base). Here base has 3 sides, so 2 × 3 = 6 edges.
