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.

[172.084, 126.948, 90.757]
129.93

[-92.0, 108.814, 164.207, 94.26, 33.74]
61.804

[39.954, 239.9, -47.987]

77.289

