6
Euclid discusses the tetrahedron in his Elements of Geometry, around 300 BC, and it is probably much older.
A tetrahedron triangular based pyramid has 6 edges, 4 faces and 4 vertices
6 edges
I am not a tetrahedron!
It means that it likes pie so much
A tetrahedron has 4 faces.
Well, a tetrahedron has four sides. A regular tetrahedron is a triangular pyramid.
A tetrahedron must be plane faced and so, it is just an ordinary tetrahedron.
He faced a tetrahedron question in the exam paper. This is a sample sentence using the word tetrahedron.
A Tetrahedron. The most common form of a tetrahedron is called a regular tetrahedron, or a pyramid
A tetrahedron has 4 faces.