This is a question that will require Pythagoras' theorem as you want to find the length of a diagonal of a triangle and are given the measurements of two sides. I have attached a picture of how to solve this problem.
To the nearest 10th of a foot, the answer is 77.6ft
If <em>z</em> ⁷ = 128<em>i</em>, then there are 7 complex numbers <em>z</em> that satisfy this equation.

![\implies z=\sqrt[7]{2^7} e^{i\frac17\left(\frac\pi2+2n\pi\right)}](https://tex.z-dn.net/?f=%5Cimplies%20z%3D%5Csqrt%5B7%5D%7B2%5E7%7D%20e%5E%7Bi%5Cfrac17%5Cleft%28%5Cfrac%5Cpi2%2B2n%5Cpi%5Cright%29%7D)
(where <em>n</em> = 0, 1, 2, …, 6)

