When you get up to many sides, I believe the correct terminology is just N-gon, where N is the number of sides. So this would be 123456-gon.
A four sided figure is called a quadrilateral.
A 12-sided figure is called a dodecagon.
A seven sided figure is called a heptagon.
A six sided figure is called a hexagon.
A 5 sided figure is called a: pentagon
An eight sided figure is called an octagon.
A 3-sided figure is called a triangle.
A four sided figure is called a quadrilateral.
A 12-sided figure is called a dodecagon.
A seven sided figure is called a heptagon.
A six-sided plane figure is called a hexagon.
A six-sided plane figure is called a hexagon.
A six sided figure is called a hexagon.
A six sided figure is called a hexagon.
Yes, an eight-sided figure is called an octagon.
An 8 sided figure is an octagon.
A 5 sided figure is called a: pentagon