Icosahedron
an edge or in more simpler term "side"
If the faces are flat, it's a line.
Isosceles TetrahedronA solid with four faces is a tetrahedron. Each of the faces is a triangle. If all the triangles are congruent, you have an isosceles tetrahedron.
a cylinder a cylinder
A vertex is the name of a corner on a solid where three or more faces meet (plural = vertices).
It could be a triangular based pyramid whose technical name is a tetrahedron.
They have compound names which use Greek prefices for the number of faces, and the suffix "hedron".So, an octahedron would be a solid with 8 faces.
Icosahedron
an edge or in more simpler term "side"
A cube has six square faces.
a triangular prism
If the faces are flat, it's a line.
an edge
The solid with 12 equal faces is a dodecahedron. A dodecahedron has 12 equal pentagon surfaces.
a triangular prism.
triangular prism