What is 70% of 210. Explain

You can set it up as a proportion
is (part)                 %
               
of( whole)        percent
you fill in the spots so it looks like this. 70% is the percent, and the 210 as the of before it, so by default, the "is" becomes x.
    x          70
   
  210     100  
then you cross multiply, so 100 times x is 100x and 210 times 70 is 14700.
so,        100x=14700
then you have to get x by itself, to cancel out x you do the opposite of the opperation which in this case means to divide, so 100x/100 is x. but what you do to one side, you have to do to another, so 14700/100=147

so X=147, or 147 is 70% of 210
you can also check your answer by multiplying the "of" you get by the percent, and you should get the "is".