23.21% is the change from 280 to 345
Calculation steps:
[( 345 - 280 ) ÷ 280] x 100 = 23.21%
Formula
Percentage change = [(345 - 280) / 280] x 100
Subtract the new number by the original number
345 - 280 = 65
65 ÷ 280 = 0.23214285714285715
0.23214285714285715 x 100 = 23.21%