An icosahedron is a regular polyhedron with 20 equilateral triangle faces.
A triangle.
It is called a cone.
pyramid
To determine your face shape look up the general guidelines for each different face shape that there is. Then look in the mirror and compare your face shape.
Well, any shape with a triangular face. I assume that you mean a shape that only has (identical) triangles for faces. There are 2: the tetrahedron with 4 triangles, and the icosahedron with 20 triangles. * * * * * What about a triangular dipyramid? Two triangular pyramids stuck together along one face?
the name of a 20 sided 3d shape is called a icosahedron
An Octagon
You take a look at what 2-D shape the face is, and then that's the name of the face.
One option would be hemidisc.
An icosagon is the name of the 20 sided polygon.
No. Every solid shape has at least one face. The closest you will get is a sphere, which has no edges or vertices, but it still has a face.
A triangle.
A face value in maths is the out-side of the shape, as to say the face of a shape. The face value is the sides of a shape.
It is a triangular prism
pyramid
It is called a cone.
To determine your face shape look up the general guidelines for each different face shape that there is. Then look in the mirror and compare your face shape.