The volume of a pyramid is given by the formula:
\[ V_{pyramid} = \frac{1}{3} \times B \times h \]
where \(B\) is the area of the base and \(h\) is the height. The volume of a rectangular prism is given by:
\[ V_{prism} = B \times h \]
Since the pyramid and the prism have congruent bases and equal heights, we can relate their volumes. The volume of the prism is three times the volume of the pyramid:
\[ V_{prism} = 3 \times V_{pyramid} \]
In this case, the volume of the pyramid is given as 48 in³:
\[ V_{prism} = 3 \times 48 , \text{in}^3 = 144 , \text{in}^3 \]
So, the volume of the prism is 144 in³.
Thus, the best answer is 144 in.³.