Answer: 28.08%
Step-by-step explanation: To find the percent increase, we divide the amount of change by the original number.
The amount of change is the difference between the two numbers which in this case is 561,000 - 438,000 and the original number is 438,000.
561,000 - 438,000 is 123,000 so we are left with 123,000 divided by 438,000 which is 0.2808. Finally, since our problem is asking us for a percent, we write 0.2808 as a percent by moving the decimal point two places to the right to get 28.08%.
So when the population changes from 438,000 to 561,000, it has increased by 28.08%.