A 5-sided 2-dimensional figure is a pentagon and a 5-sided 3-dimensional shape is a pentahedron.
Octahedron
In geometry a 29 sided shape is referred to as an icosikaidigon. The shape closely resembles an 3 dimensional octagon.
a polyhedron (if the shape is 3 dimensional) a polygon if it is a planar shape.
2 or 3 dimensional?
A 5-sided 2-dimensional figure is a pentagon and a 5-sided 3-dimensional shape is a pentahedron.
An octagon is an 8 sided 2 dimensional shape. A cylinder with the base of a hexagon (6 sided shape) would be an 8 sided 3 dimensional shape.
This question is faulty. Only 2-dimensional shapes can have their sides counted. For a 3-dimensional shape, you must count either edges or faces.
Triacontatetragon. Most mathematicians would call it a "34-gon."
An 18 sided shape is called a octadecagon. This refers to both 2 dimensional and 3 dimensional shapes in a mathematical sense.
Octahedron
A heptagon.
In geometry a 29 sided shape is referred to as an icosikaidigon. The shape closely resembles an 3 dimensional octagon.
a polyhedron (if the shape is 3 dimensional) a polygon if it is a planar shape.
2 or 3 dimensional?
A triangle is a 3 sided shape. There are a few types, Isosceles, Scalene (Acute and Obtuse), Equilateral and the Right angle triangle.
A 3 dimensional figure