how much wrapping paper is needed to cover a rectangular box that is 18 inches by 16 inches by 4 inches

The surface consists of three pairs of rectangular faces, right? So it will take

2(18*16 + 18*4 + 16*4) = 848 in^2

To calculate the amount of wrapping paper needed to cover a rectangular box, you need to find the surface area of the box.

A rectangular box consists of six faces: the top, bottom, front, back, left, and right.

The formula to find the surface area of a rectangular box is:
Surface Area = (2 * l * w) + (2 * w * h) + (2 * l * h)

where:
l = length of the box
w = width of the box
h = height of the box

Let's plug in the values for your box:
l = 18 inches
w = 16 inches
h = 4 inches

Surface Area = (2 * 18 * 16) + (2 * 16 * 4) + (2 * 18 * 4)
= 576 + 128 + 144
= 848 square inches

Therefore, you would need 848 square inches of wrapping paper to cover the entire surface of the rectangular box.