Given the following set of ratios:


To be able to determine if the given sets are equivalent ratios, they must a common constant, k, which is x/y.

Let's treat the ratio as x:y and find their common constant, k.
At 4:5 and 8:10,


Since the two ratios have the same common constant, k = 4/5, the two ratios are equivalent.
At 18:3 and 6:1,


Since the two ratios have the same common constant, k = 6, the two ratios are equivalent.