It is a Heptagon.
A nonagon is a 2 dimensional shape that has nine sides. A polygon on the other side refers to a plane that is 2D and has three straight sides.
It's called a "polygon".
It is the decagon.
Hexagon
A 2D shape with 9 sides is called a Nonagon.
Square
Tetradecagon.
Octagon
hexagon
It is a Heptagon.
A triangle as no other 2d shape can have 3 sides.
A ten-sided 2D polygon is known as a decagon.
in 2d shapes a quadrilateral
A quadrilateral.
The shape of 2D is a flat surface.
A polygon with 20 sides is called either a 20-gon or an icosagon.