percent formula : is/of = %/100
is = 187.05
of = 645
% = x
now we sub
187.05/645 = x/100
this is a proportion and we now cross multiply
645(x) = (187.05)(100)
645x = 18705
x = 18705/645
x = 29
so... 187.05 is 29% of 645
u can use the percent formula on all percent problems...just make sure u sub the numbers in the right spot.