Given the following set of ratios:
![4\colon5\text{ and 8:10}](https://img.qammunity.org/2023/formulas/mathematics/college/53pl6vy716x2jedz87qi7xeq4lhj4daf74.png)
![18\colon3\text{ and 6:1}](https://img.qammunity.org/2023/formulas/mathematics/college/gpdvl1lbr84n495oqcfhb5wm5oqaled4l3.png)
To be able to determine if the given sets are equivalent ratios, they must a common constant, k, which is x/y.
![\text{ k = }(x)/(y)](https://img.qammunity.org/2023/formulas/mathematics/college/rxsq9ezjzmdmgewzpb0afu7jnq6c2bl19e.png)
Let's treat the ratio as x:y and find their common constant, k.
At 4:5 and 8:10,
![k_(4\colon5)\text{ = }(4)/(5)](https://img.qammunity.org/2023/formulas/mathematics/college/b4w5es8081ru9x2ddlnznur2zde1cred4i.png)
![k_(8\colon10)\text{ =}(8)/(10)\text{ = }((8)/(2))/((10)/(2))\text{ = }(4)/(5)\text{ ; simplified}](https://img.qammunity.org/2023/formulas/mathematics/college/4no41t0fllzp7du24ber7wtwtm4jpr54sw.png)
Since the two ratios have the same common constant, k = 4/5, the two ratios are equivalent.
At 18:3 and 6:1,
![\text{ k}_(18\colon3)\text{ = }(18)/(3)\text{ = }((18)/(3))/((3)/(3))\text{ = }(6)/(1)\text{ = 6}](https://img.qammunity.org/2023/formulas/mathematics/college/c6yvr5gawppz2dpq5udaziljijacooh0uz.png)
![\text{ k}_(6\colon1)=(6)/(1)\text{ = 6}](https://img.qammunity.org/2023/formulas/mathematics/college/tcmizq4dvli11oj91jh12cmt5p1s9pj6rf.png)
Since the two ratios have the same common constant, k = 6, the two ratios are equivalent.