Answer:
The slant height is 28 inches
Explanation:
The slant height of a pyramid
Given a square base pyramid of side 2a and height h, the slant height is calculated as follows:

The attached image shows the relationship between the lengths.
There is no specific information about the dimensions provided in the question, but I'm assuming this:
h = 22.4 in
a = 16.8 in
The slant height is:


s = 28 in
The slant height is 28 inches