Tetrahedron.
Chat with our AI personalities
The suffix "hedron" implies 3D. The 2D suffix is "gon"
There can be no closed 3D shape with only one square and 3 triangles.
A 'hedron' from Latin. Hence 'polyhedron' a many sided three dimensional object.
A 3D shape with all triangular faces can be a tetrahedron pyramid.
A 2-d shape. The suffix -gon indicates a 2-d shape while -hedron indicates a 3-d shape.