Looking at figure A, we have a prism with a triangular base that looks like a right triangle.
Since the prism has a right triangular base, the base shape is a right triangle (shape 5).
Looking at figure B, we have a prism with a pentagonal base.
Since the prism has a pentagonal base, the base shape is a pentagon (shape 1).
Looking at figure C, we have a prism with a triangular base that looks like an equilateral triangle.
Since the prism has an equilateral triangle base, the base shape is an equilateral triangle.(shape 4).
Looking at figure D, we have a prism with a triangular base that looks like an equilateral triangle.
Since the prism has an equilateral triangle base, the base shape is an equilateral triangle.(shape 4).
