Three ratios that are equal to 40/50, 75/100, and 21/18 are 4/5, 3/4, and 7/6. The question is essentially asking you to simplify fractions. For example, 8/10 can also be represented as the ratio 8:10. This fraction can be simplified to 4/5, and the ratio 4:5 is the same as the ratio 8:10.