Definition: In this task you will be given a list of numbers and you need to find the mean (average) of that list. The mean of a list can be found by summing every number in the list then dividing the result by the size of that list. The output should be rounded to 3 decimal places.
Input: [86.433, 138.224, 193.806, 53.559, 40.299, 15.046, 212.04, 174.212, 172.282]

120.656