<h2>Answer:</h2>
The height of the box is:
4 ft.
<h2>Step-by-step explanation:</h2>Let "h" denotes the height of the box.
Length of box is denoted by "l"
and breadth or width of box is denoted by "b"
We are given l=18 ft
b=8 ft.
Also we are given surface area of rectangular box= 496 ft²
As we know that the surface area of box is given by:
i.e.
Divide both side by 2.
on dividing both side by 26 we get:
Hence, the height of the box is:
4 ft.