How about a cone or a pyramid
Such a figure is a pyramid.
A 3D shape with one base and three faces can only have triangular faces.
A polygonal pyramid.
a polygonal prism or a polygond
A pyramid is a solid figure with one vertix.
A cone, possibly.
How about a hemisphere ?
A hemisphere is one example.
Because the base of a cone is round, it is the only three dimensional figure with only one vertex.
pyramid or cone
a pyramid yeah
A cone has a round base and a narrowing round top. I hope this answers your question!
A sphere would fit the given description
If it has a square base, one. Squares don't crop up all that often.
It is called a face.