Yuhhhhhhhhhh 82828191919110010202929229
3.5 miles per hour :) hopefully this helps!
If you notice, the container is really just two circles, with a diameter of 4 each, and a square with sides of 10.5.
now, if we just get the area of each circle, keeping in mind their radius is half of the diameter, namely r = 2, and get the area of the 10.5x10.5 square, sum them up, that'd be the surface area of the container.
All you do is measure it with a ruler and for every 1 cm you get multiply it by 8.5ft.
so for example if you got 6cm then you would multiply it by 8.5ft and your answer would be 51ft.