61.25% is the change from 400 to 645
Calculation steps:
[( 645 - 400 ) ÷ 400] x 100 = 61.25%
Formula
Percentage change = [(645 - 400) / 400] x 100
Subtract the new number by the original number
645 - 400 = 245
245 ÷ 400 = 0.6125
0.6125 x 100 = 61.25%