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: [-82.27, 46.742, -60.547, 97.652, 121.66, 104.393, -43.603, 125.281, 42.318, 200.514]

55.214