Answer:
24.7 inches
Step-by-step explanation:
Length = 18 inches
Width = 12 inches
Height = 12 inches
Length of the longest diagonal,d = length^2 + width^2 + height^2
d^2 = 18^2 + 12^2 + 12^2
d^2 = 324 + 144 + 144
d^2 = 612
d = √612
= 24.7 of inches
Length of the longest diagonal in the box = 24.7 inches
