285.32% is the change from 109 to 420
Calculation steps:
[( 420 - 109 ) ÷ 109] x 100 = 285.32%
Formula
Percentage change = [(420 - 109) / 109] x 100
Subtract the new number by the original number
420 - 109 = 311
311 ÷ 109 = 2.853211009174312
2.853211009174312 x 100 = 285.32%