As far as I can tell, the definition of margin of error involves more than you're given in this exercise (for example, you should know how many people were surveyed, the standard deviation, etc etc).
So, I assume that you're looking for a "simplified" interpretation of the margin of error: the estimate are around 80%, with a margin of 4% up or down.
So, you would be claiming that 80% of people is satisfied, with a margin of uncertainty of 4% (so it can be a minimum of 80-4=76 and a maximum of 80+4=84)
