-75% is the change from 360 to 90
Calculation steps:
[( 90 - 360 ) ÷ 360] x 100 = -75%
Formula
Percentage change = [(90 - 360) / 360] x 100
Subtract the new number by the original number
90 - 360 = -270
-270 ÷ 360 = -0.75
-0.75 x 100 = -75%
Example