11.25% is the change from 80 to 89
Calculation steps:
[( 89 - 80 ) ÷ 80] x 100 = 11.25%
Formula
Percentage change = [(89 - 80) / 80] x 100
Subtract the new number by the original number
89 - 80 = 9
9 ÷ 80 = 0.1125
0.1125 x 100 = 11.25%
Example