A solid with four faces for maths is a tetrahedron.
Triangle
Four.
Four
A square is not a solid figure at all. It's a flat figure, with four congruent faces and four congruent angles.
By its very nature of being a triangle, and a 2D shape, a triangle cannot have four plane faces. However, a tetrahedron is a polyhedron made up of four triangular faces.
A polyhedron (solid shape formed by plane faces) with four faces is called a tetrahedron.
triangle based pyramids
Isosceles TetrahedronA solid with four faces is a tetrahedron. Each of the faces is a triangle. If all the triangles are congruent, you have an isosceles tetrahedron.
four triangle faces.
A solid with four faces for maths is a tetrahedron.
Triangle
Rectangles are plane (2-dimensional) polygons. Only solid (3-dimensional) polyhedrons have faces.
A four-faced solid is called a tetrahedron.
pyramid
four
Four.