A five sided 2 dimensional object is called a pentagon.
A nine-sided object is known as a nonagon.
If it is 3 dimensional it is an icosahedron If it is 2 dimensional it is an icosagon
Octagon.
A triangular pyramid.
A five sided 2 dimensional object is called a pentagon.
A nine-sided object is known as a nonagon.
If it is 3 dimensional it is an icosahedron If it is 2 dimensional it is an icosagon
Decagon.
octagon
Octagon.
hendecagon
the Greeks used prefexes up to ten, modernly we have sdded dodecagon for a twelvesided object and undecagon for an eleven sided object so the propor name would be a 27 sided object.
A hexakaidecagon (hexadecagon).
Decagon
HEXADECAHEDRON is the correct name for a 16 sided 3D object
Pentagon 2d shape is a pentagon 3d object is a pyramid.