All the prisms and pyramids are polyhedrons.

A tetrahedron is the only pyramid which can be a regular polyhedron.

The line segments where the faces of a polyhedron meet are called edges.

$\mathrm{F}+\mathrm{E}=\mathrm{V}+2$ is called an Euler's formula.

In any prism number of faces is $2$ more than number of sides of polygonal base.

In any pyramid number of edges is twice the number of sides of polygonal base.

State which of the following statements are true $\left(\mathrm{T}\right)$ or false $\left(\mathrm{F}\right)$:

An octagonal prism has $18$ vertices.

All pyramids are prisms.

Lateral faces of a pyramid are triangles.