pentagonal pyramid
A 3D shape with one base and three faces can only have triangular faces.
Only one; a triangle is a 2D shape, not a 3D shape. Usually only 3D (or more) shapes are considered to have 'faces'.
tetrahedra (a pyramid with a triangular base)
Nonahedron.
A cuboid.
The simplest such shape is PYRAMID.
A 3-D shape that has 8 faces is a hexagonal prism. This is a shape that is formed on a hexagon-shaped base.
A square base pyramid
A rectangular prism, it has 6 rectangular faces.
The 3d shape that have five faces would be a triangular prism **************** or a pyramid
The 3D shape you are describing is a pentagonal pyramid. It has a pentagonal base with five sides, and five vertices where the triangular faces meet. The three rectangle faces are lateral faces that connect the triangular base to the apex of the pyramid. The pentagonal pyramid is a type of pyramid with a polygonal base and triangular faces.
There is no such thing as a 3d triangle. A 3d shape which has only equilateral triangular faces can be a tetrahedron which has 4 faces or an icosahedron which has 20.