For perimeter you add all of the sides but for area you multiply each side
Geometric sequence

r=common ratio
a1=first term
find r
a1=8
a6=-8192


divide both sides by 8

take 5th root of both sides
-4=r
sub



You can set this up as 2 fractions equal to each other, like ratios.
18/11=108/x
Cross multiply and you get 18x=1,188
Now divide both sides by 18 and get x.
x=66.
If the height of the building is 108ft, the width is 66ft.
quotient is divide 7 ÷ -3/6
now flip the -3/6
7/1 x -6/3 = -42 / 3 or -14