Answer:
The answer is a rectangle.
Explanation:
A triangular prism was sliced parallel to its base. What is the shape of the cross section shown in the figure?
The answer is rectangle. If the base is a rectangle and we slice it parallel to the base in the same direction as the base, we will get smaller and smaller rectangles with each slice.
This can be clear with the picture attached. If we slice parallel to rectangular base, the cross section will be a rectangle.