A polyhedron with 20 faces is called an icosahedron.
A one-hundred sided polyhedron is called a hecatohedron, comming from the Greek Hecto- meaning one-hundred and -hedronmeaning a three-dimensional figure.
Octohedron
There is no name for a five sided regular polygon. A five sided polyhedron is called a pentahedron.
A shape in 2D with n sides is called an n-gon. In higher dimensions, a shape with n sides is called an n-sided polyhedron.
A polyhedron with 20 faces is called an icosahedron.
nonahedron
An octahedron, which looks like 2 pyramids glued bottom to bottom.
A one-hundred sided polyhedron is called a hecatohedron, comming from the Greek Hecto- meaning one-hundred and -hedronmeaning a three-dimensional figure.
A 20-sided polyhedron is called an icosahedron. It has 20 equilateral triangle faces, 30 edges, and 12 vertices. It is a regular convex polyhedron with rotational symmetry.
Octohedron
There is no name for a five sided regular polygon. A five sided polyhedron is called a pentahedron.
A 60 sided polygon is a Hexacontagon.
a polyhedron (if the shape is 3 dimensional) a polygon if it is a planar shape.
A 120-sided polyhedron is a hecatonicosahedron.
A shape in 2D with n sides is called an n-gon. In higher dimensions, a shape with n sides is called an n-sided polyhedron.
A 2D seven sided figure is called a heptagon. A 3D seven faced polygon is called a heptahedron.