A 3D shape with all triangular faces can be a tetrahedron pyramid.
There can be no closed 3D shape with only one square and 3 triangles.
Tetrahedron.
The simplest such shape is PYRAMID.
Yes.
An icosahedron.
There can be no closed 3D shape with only one square and 3 triangles.
Tetrahedron.
A tetrahedron has four equilateral triangles as sides
There is no 3D shape with 6 faces: 4 rectangles and 2 triangles. See the link for all forms of hexahedra.
The simplest such shape is PYRAMID.
Square pyramid
Yes.
The three-dimensional shape consisting of 4 triangles is called a pyramid, or a triangular prism.
duodecahedron is a 3D shape that has 20 triangles as it's base
A triangular pyramid.
An icosahedron.
Tetrahedron or Triangular Pyramid