A 12 sided figure is called a dodecagon.
It is called an 'Irregular Hexagon'
A twenty sided, 2D figure is called an icosagon.
A two-dimensional eleven-sided figure is called a hendecagon.
A plane figure bounded by some numbers of straight sides is called a polygon. Thus a polygon with ten-sided is called a decagon.
an four sided figure is called a quadrilateral.
quadrilateral
A 12 sided figure is called a dodecagon.
A heptagon. Note that an irregular heptagon can have even sides - if the angles are not all the same.
parallelogram
A 5-sided figure is called a "Pentagon".
A 10 sided shape is a decagon
It is called an 'Irregular Hexagon'
A plane figure with a googol sides is called a googolgon.
quadrilateral
a 12 sided figure is called a dodecagon
A non-descript four sided figure is a quadrilateral.