Introduction
In geometry, a Platonic solid is a convex, regular polyhedron in three-dimensional Euclidean space. Being a regular polyhedron means that the faces are congruent (identical in shape and size), regular polygons (all angles congruent and all edges congruent), and the same number of faces meet at each vertex. There are FIVE (and only five) Platonic solids:-
Geometers have studied the Platonic solids for thousands of years. They are named for the ancient Greek philosopher Plato. who hypothesized in one of his dialogues, the Timaeus, that the classical elements were made of these regular solids.
Note. Geometer (plural Geometers) A mathematician who specializes in geometry.
Tetrahedron (Four faces) -
Tetrahedron
A Tetrahedron is a polyhedron composed of four triangular bases, six straight edges, and four vertex corners.
∴ A Tetrahedron is also known as a triangular pyramid.
A tetrahedron is formed by placing three equilateral triangles at a vertex (sum of angles at vertex is 180°). It has 4 vertices, 6 edges, and 4 faces. Each face is an equilateral triangle.
Of the Platonic solids, the tetrahedron has the smallest volume for its surface and is the only one that has fewer than five faces. It is one kind of a pyramid.
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