What is the name of a polyhedron whose faces are all triangles?

What is the name of a polyhedron whose faces are all triangles?

• A. Tetrahedron
• B. Cube
• C. Octahedron
• D. Dodecahedron

Answer: (A)

A polyhedron with all faces as triangles is built entirely from triangular faces. The tetrahedron is the simplest example of this kind: it has four triangular faces arranged as a triangular pyramid, so every face is a triangle. The cube has square faces and the dodecahedron has pentagonal faces, so they don’t fit. An octahedron also has triangular faces, so it’s another valid example, but among the given options the tetrahedron clearly matches the description.

A polyhedron with all faces as triangles is built entirely from triangular faces. The tetrahedron is the simplest example of this kind: it has four triangular faces arranged as a triangular pyramid, so every face is a triangle. The cube has square faces and the dodecahedron has pentagonal faces, so they don’t fit. An octahedron also has triangular faces, so it’s another valid example, but among the given options the tetrahedron clearly matches the description.