Enrique has to pay 80% of a $200 phone bill. Explain how to use equivalent ratios to find 80% of $200.

First, write 80% as 80 /100 . Then write an equivalent ratio that has the answer in the numerator and 200 in the denominator. 100 x 2 is 200, so 80 x 2 will be the answer. 80 x 2 = 160. The answer is $160.