Decagon
A decagon.
ninagon
A pentagon
The name is "ERROR". A decagon cannot have 11 sides.
Hendecagon has 11 sides
a parallelogram
Yes a trapezium is a 2 dimensional shape and belongs to the class of polygons known as quadrilaterals because if has 4 sides
a hendecagon has 11 sides =)
It is an undecagon
It is called Enneagon for eleven sides.
There is no specific term that distinguished between shapes with more than 11 sides from those with up to 11 sides.