Octagon
A shape with 18 edges is called an 18-gon or an 18-sided polygon in two dimensions. In three dimensions, a polyhedron with 18 edges could be a specific type of structure, such as a triangular prism with additional faces or other complex polyhedral forms. An example of a polyhedron with exactly 18 edges is the truncated tetrahedron. The characteristics of such shapes can vary widely depending on the arrangement and number of vertices and faces.
Shapes with 12 to 20 sides are named as follows: a 12-sided shape is called a dodecagon, a 13-sided shape is a triskaidecagon, a 14-sided shape is a tetradecagon, a 15-sided shape is a pentadecagon, a 16-sided shape is a hexadecagon, a 17-sided shape is a heptadecagon, an 18-sided shape is an octadecagon, a 19-sided shape is a nonadecagon, and a 20-sided shape is an icosagon.
If you say this shape is 18 sided i would guess it has 18 sides. ;)
The name of a 18 sided polygon is Octadecagon.
The interior angles of an 18 sided polygon add up to 2880 degrees
A shape with 18 edges is called an 18-gon or an 18-sided polygon in two dimensions. In three dimensions, a polyhedron with 18 edges could be a specific type of structure, such as a triangular prism with additional faces or other complex polyhedral forms. An example of a polyhedron with exactly 18 edges is the truncated tetrahedron. The characteristics of such shapes can vary widely depending on the arrangement and number of vertices and faces.
All I can tell you is that a 16 sided shape is called a Hexadecagon
If it is a 2 dimentional shape it is called an 'octadecagon'
Octadecadron
An 18 sided shape is called a octadecagon. This refers to both 2 dimensional and 3 dimensional shapes in a mathematical sense.
An eighteen-sided shape is called an octakaidecagon, or octadecagon.
A polygon refers to a plane figure that has at least three straight sides and angles. An 18 sided shape is called an octadecagon or octakaidecagon.
Shapes with 12 to 20 sides are named as follows: a 12-sided shape is called a dodecagon, a 13-sided shape is a triskaidecagon, a 14-sided shape is a tetradecagon, a 15-sided shape is a pentadecagon, a 16-sided shape is a hexadecagon, a 17-sided shape is a heptadecagon, an 18-sided shape is an octadecagon, a 19-sided shape is a nonadecagon, and a 20-sided shape is an icosagon.
Two polyhedrons have 18 edges: truncated tetrahedron and hexagonal prism.
Tetrahaidecahedron
octadecagon
enneadecagon or enneakaidecagon