Two.
Chat with our AI personalities
A circle has no vertices and it has one face. It could also be argued that a circle is the limiting form of a regular polygon with an infinite number of vertices.
A semi-circle is a two dimensional shape.
4 faces and 2 vertices.
A circle has no vertices and is round.
There are many shapes that have fewer than 3 vertices like the circle, hyperbola, semi circle, and many others. However if you are only talking about polygons then there is no actual shape with fewer than 3 vertices that you can find in a real life situation but they do have names for these shapes. A 2-sided polygon is known as a digon. A 1-sided polygon is known as a monogon. These shapes only exist in theory however and not in real life.