There are several triangular polyhedra. The simplest is a tetrahedron with 4 faces, but you can have a triangular dipyramid (two tetrahedra stuck together along one face) which has 6 faces. Then there is the icosahedron with 20 faces. The tetrahedron and icosahedron are Platonic solids, but there are many more.
four triangle faces.
There are 2 triangle base faces, and 3 rectangle faces. 5 total faces.
5 faces
1
5
7.5
1
3
a 2d triangle has 1 face known as a plane but a triangular prism has 4 faces
trianle have no faces, because it is 2D figure.
One
None.