Concept:A triangular pyramid (also known as a tetrahedron) has a triangular base and three triangular lateral faces. For any pyramid with a base of n sides, the number of faces is n+1 and the number of edges is 2n.
Explanation:The base of a triangular pyramid is a triangle, so n = 3.
Faces = 1 base + 3 lateral faces = 4 faces.
Edges = 3 base edges + 3 slant edges = 6 edges.
Vertices = 3 base vertices + 1 apex = 4 vertices (which also satisfies Euler’s formula V − E + F = 2).
Thus, a triangular pyramid has 4 faces and 6 edges.
Answer:Option B: 4 faces and 6 edges.