To find the percentage difference between two numbers, we first need to calculate the absolute difference between them. In this case, the absolute difference between 260 and 175 is 85.

Next, we need to find the average of the two numbers. The average of 260 and 175 is (260+175)/2 = 217.5.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 260 and 175 is (85/217.5) x 100 = 39.08%.

Therefore, the percentage difference between 260 and 175 is 39.08%. This means that the two numbers differ by 39.08% of their average value.