Three.
An octagon has 8 vertices.
A cube has eight (8) vertices (corners).
Heptahedra can have between 6 and 10 vertices.
8
courners, intersects
A pyramid does.
A triangular pyramid has four triangular faces.
None, because there can be no such thing as a triangular square. If it is triangular it cannot be a square, if it is a square it cannot be triangular.
Triangular prism: 6 Triangular pyramid: 4 Answer: 2
2 triangles are in a triangular prism
Four.