Carl K. answered 09/15/19
Assistant Professor of Family Medicine
You refer to the area of a pie. Each slice would represent 33.333%. You can draw a line over the last digit, which indicates mathematically that the decimal repeats, and you would accurately describe the size of the slice.
You make it difficult. You can precisely slice the pie into thirds, where each slice is exactly the same size as the other two. There are several methods of doing this geometrically.
You use the situation where a pie slice represents a percentage of the whole. The whole is always 100% and can easily be split three ways, by geometry.
You may wish to look up real numbers and rational numbers. 1/3 is both.