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: [28.856, -75.471, 62.622, 212.135, -44.995, 212.972, 12.709, 3.732, 120.603]

59.24