I am confused with regards to the unit. You wrote cm cubic inches. So, I'll just use cubic unit.
Given:
Volume of rectangular pyramid is 125 cubic unit
Volume of rectangular pyramid = (length * width * height) ÷ 3
Volume of rectangular prism = length * width * height
The main difference between the two volumes is the present of 3.
Volume of rectangular prism = Volume of rectangular pyramid * 3
V = 125 cubic unit * 3 = 375 cubic unit