There is no polyhedron with only three sides - a polyhedron being a 3-D shape with plane sides. Once you remove the restriction of plane sides you get several options, some of which are:
A cylinder or a cylindrical shape with partial spheres at each end (like a medicine capsule).
A segment of a torus (a doughnut with a chunk cut out of it).
A spherical wedge - like a segment of a round cheese (that is, real cheese, not the processed plastic that some people consider cheese).
a henagon is an 11 sided 2-D shape and a 3-D is called an hendecahedron.
A dodecahedron is a 3-d shape with 12 faces that are regular pentagons.
A 5-sided 2-dimensional figure is a pentagon and a 5-sided 3-dimensional shape is a pentahedron.
A rhombus is a four sided polygon, a quadrilateral. It is a 2d shape. 2d shapes have 2 dimensions, like length and width. 3d shapes have 3 dimensions, like length, width and depth.
3D is a term used to describe space figures. They occupy space and have volume. A 3D shape is also called solid figure , solid shape , space figure and 3D figure.
a henagon is an 11 sided 2-D shape and a 3-D is called an hendecahedron.
A 14-sided and 3-dimensional shape is called either a tetrakaidecahedron or tetradecahedron. This 14-sided polyhedron can have six quadrilateral and eight hexagonal faces.
An 18 sided shape is called a octadecagon. This refers to both 2 dimensional and 3 dimensional shapes in a mathematical sense.
A dodecahedron is a 3-d shape with 12 faces that are regular pentagons.
It has 5 corners if it is a 3D shape like a piramid but if it is 2D it is 3
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.
A 5-sided 2-dimensional figure is a pentagon and a 5-sided 3-dimensional shape is a pentahedron.
Typically this is called a triangle. :)
A 3 sided shape is a triangle. A 4 sided shape could be a square or rectangle.
It is a noun- the name for a 3 sided shape.
A triangle is a 3 sided shape. There are a few types, Isosceles, Scalene (Acute and Obtuse), Equilateral and the Right angle triangle.
A triangle only has 3 sides, but a 10 sided shape is called a decagon