What Is a 3-D Triangle Called?
A three-dimensional shape that is made up of four triangles is called a tetrahedron. If it is a regular tetrahedron, then it contains four equilateral triangles as its faces. A regular tetrahedron is also a platonic solid.
Platonic solids are polyhedra that have faces which are regular polygons with equal shapes and sizes. There are five platonic solids that include the cube, octahedron, icosahedron, dodecahedron and the tetrahedron.
The tetrahedron has four vertices and six edges. The formula for its surface area is given as √3 × (Edge Length)2. The volume formula is (√2)/12 × (Edge Length)3.