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: [210.982, -37.264, 192.327, -54.075, -77.356, 193.668, 37.14, 56.456, 243.352]

85.026