Your thinking of the six sided die.
it's a pyramid with 5 sides.
Triangular based pyramid
a triangular prism
triangular cone
a triangular prism.
Such at figure - as described - could not be made as a solid geometric shape.
it's a pyramid with 5 sides.
It is a pyramid
A 3D shape with one base and three faces can only have triangular faces.
A triangular prism.
Four triangular faces.
A Triangular Prism
Triangular based pyramid
triangular prism
a triangular prism
Triangular prism.
a triangular prism!