39.53% is the change from 645 to 900
Calculation steps:
[( 900 - 645 ) ÷ 645] x 100 = 39.53%
Formula
Percentage change = [(900 - 645) / 645] x 100
Subtract the new number by the original number
900 - 645 = 255
255 ÷ 645 = 0.3953488372093023
0.3953488372093023 x 100 = 39.53%