In the percent proportion, the ratio of a part of something (part) to

the whole (base) is equal to the percent written as a fraction. \ \

The part a = 6  \ \

The base b = 15 \ \

Replace a with 6 and b with 15.

         (Means-extremes Property of proportion: If , then ad = bc.)

   (Divide each side by 15)

              (Cancel common terms)

                         (Simplify:)

Six is 40% of 15.