Answer:
The length of the longest metal rod that can be sent is 12 inches.
Explanation:
As given, the only boxes available for shipping are 7-inch cubes. As Jorge needs to ship a thin metal rod to a metalworking shop, he will put the rods diagonally or space diagonally in the box.
The space diagonal of a cube can be found by the formula :
=

Here, x is 7 inches.
So, Diagonal is =

=
inches.
Rounding this to nearest whole number we get 12.
So, the length of the longest metal rod that can be sent is 12 inches.