343.75% is the change from 80 to 355
Calculation steps:
[( 355 - 80 ) ÷ 80] x 100 = 343.75%
Formula
Percentage change = [(355 - 80) / 80] x 100
Subtract the new number by the original number
355 - 80 = 275
275 ÷ 80 = 3.4375
3.4375 x 100 = 343.75%
Example