To find the percentage difference between two numbers, we first need to find the absolute difference between them. In this case, the absolute difference between 289 and 180 is 109.

Next, we need to find what percentage this absolute difference is of the average of the two numbers. The average of 289 and 180 is (289+180)/2 = 234.5.

So, the percentage difference between 289 and 180 is (109/234.5) x 100% = 46.5%.

This means that the difference between 289 and 180 is 46.5% of the average of the two numbers.