Final answer:
The largest unit cube that can pack a rectangular prism with dimensions of 2½ in. and 7/2 in. has an edge length of 0.5 in.
Step-by-step explanation:
To determine the edge length of the largest unit cube that can be used to pack the given rectangular prism with dimensions of 2½ in. and 7/2 in., we need to find the greatest common divisor that can fit evenly into both dimensions.
In this case, since 7/2 can be simplified to 3.5 in., and 2½ in. can be expressed as 2.5 in., the largest cube that fits into both dimensions will be a cube with an edge length of 0.5 in., which is the largest fraction common to both dimensions.