For this case we have the following relationship between the volumes:

Where,
V2: Volume of the triangular prism after applying the scale factor on each side
V1: Original volume of the triangular prism
k: scale factor
Substituting values we have:

Rewriting:
Answer:
the volume of the prism if each side is dilated by a factor of 1/3 will be
V = 1 cubic unit