There are infinitely many such shapes.
tetrahedron
Pyramid with a hexagonal base
A 3D shape with one base and three faces can only have triangular faces.
my Answer that it is a triangle because a triangle has 3 sides and not 4 sides witch the triangle names are isosceles triangle and equilateral and scalene and right triangle and obtuse triangle ans acute triangle
-3
A hexagonal pyramid
Yes, a triangle has 3 sides, and the base is one of those.
most likely a triangular prism
what shape is not a triangle but has 3 sides
One answer is triangle
Octohedron
It could possibly be a triangle depending on its base