B. Vertical line of symmetry
The answer to the question is 3.5 hundreds
To find the increase from 1997 to 1998, you could substitute in numbers and then determine the percent increase based on those numbers.
Ex: 500 to 1000 (96-97)
1000 to 2000 (97-98)
Percent increase is (2000-1000)/1000 or 100% increase.
Testing another set of numbers will result in the same thing.
Ex: 200 to 400 (96-97)
400 to 800 (97-98)
Percent increase is (800-400)400 or 100% increase.
The percent increase is 100%.
