The lower base of the frustum shown in the figure is a square 8ft on each side. The upper base is a square 4ft on each side. In the altitude is 6ft, find the slant height

A - 4ft

B - 5.66 ft

C - 6 ft

D - 6.32 ft

The answer is D 6.32

S = the slant Height

Then we need to get the apothem of the lower and upper base

S^2 = (apothem of the lower base - apothem of the upper base) ^2 + (height) ^2

and they would be like this:

apothem of the lower base = 8 / 2*tan (90/2) = 4

apothem of the upper base = 4 / 2*tan (90/2) = 2

S^2 = (4 - 2) ^2 + (6) ^2

S^2 = 2^2 + 6^2

S^2 = 4 + 36

S^2 = 40

S = 6.32