304.76% is the change from 210 to 850
Calculation steps:
[( 850 - 210 ) ÷ 210] x 100 = 304.76%
Formula
Percentage change = [(850 - 210) / 210] x 100
Subtract the new number by the original number
850 - 210 = 640
640 ÷ 210 = 3.0476190476190474
3.0476190476190474 x 100 = 304.76%