Answer:
A rectangle
Step-by-step explanation:
The complete question is
A triangular prism was sliced perpendicular to its bases and through a vertex. What is the shape of the cross section shown in the figure?
we know that
In a triangular prism, each cross-section parallel to the triangular base is a triangle congruent to the base, and the shape of the cross section of the figure that is perpendicular to the triangular bases and passes through a vertex of the triangular bases is a rectangle
See the attached figure to better understand the problem
