Concept:All given solids except the Pentagonal Prism have all faces of the same shape (triangles or squares).Explanation:Octahedron has 8 triangular faces. Cube has 6 square faces. Tetrahedron has 4 triangular faces. These are regular polyhedra with identical face shapes. Pentagonal Prism has 7 faces: two pentagonal bases and five rectangular lateral faces. Its faces are not all the same shape. Hence, it is the odd one out.
