Need Help with trunk spare tire well dimensions

and to toss some math into the equation, if A2 + B2 = C2 then the largest fuel cell you can fit is A2 + B2 = (22)2
A2 + B2 = 484
assuming that you are getting a square fuel cell then A2 and B2 are equal so we can find either by taking half of C2 which is 242
the root of 242 = 15.5 so the biggest SQAURE fuel cell you can fit is 15.5 by 15.5

hope this helps :)

(feel free to redo the math, I never was too good at it)