The volume \( V \) of a rectangular prism is given by the formula:
\[ V = \text{length} \times \text{width} \times \text{height} \]
The volume \( V \) of a rectangular pyramid with the same base and height as the prism is given by:
\[ V = \frac{1}{3} \times \text{base area} \times \text{height} \]
Since the base area of the rectangular pyramid is the same as that of the prism, we can say:
\[ \text{base area} = \text{length} \times \text{width} \]
Thus, the volume of the pyramid can be expressed as:
\[ V = \frac{1}{3} \times \text{length} \times \text{width} \times \text{height} = \frac{1}{3} \times \text{Volume of the prism} \]
Given that the volume of the rectangular prism is 600 in³, the volume of the rectangular pyramid is:
\[ V = \frac{1}{3} \times 600 = 200 , \text{in.}^3 \]
Therefore, the answer is:
200 in.³ or 200 in. cubed.