Answer:
The slant height is 6.32 ft ( approx )
Explanation:
Since, the slant height formula of a square frustum,

Where,
is apothem of the lower base,
is the apothem of the upper base,
And, h is the altitude,
Given,
The lower base is a square 8 ft on each side,
So, its apothem,

Similarly,
The upper base is a square 4 ft on each side,

Also, h = 6 ft,
Hence, the slant height of the given frustum is,