When trying to figure out how long can be the longest rod you can fit if you have a rectangular box that has the measurements 8ft x 12ft x 8 ft. The length is 12 the width is 9 and the height is 8.

The longest rod that can fit in a rectangular box is 17 feet long.

Given:

Length = 12 ft

Width = 9 ft

Height = 8 ft

We need to get the diagonal of the rectangular box. The rectangular box is three dimensional. So, the formula to get it is:

a² + b² + c² = d²

a = width; b = length; c = height

9² + 12² + 8² = d²

81 + 144 + 64 = d²

289 = d²

√289 = d

17 = d