Final answer:
After cross-multiplying the terms of the ratios 5:3 and 20:9, we see that the results are not equal (45 ≠ 60), hence the ratios do not form a proportion.
Step-by-step explanation:
To determine if the ratios 5:3 and 20:9 form a proportion, you compare the ratios by cross-multiplying the corresponding terms of the ratios. In mathematical terms, for two ratios a:b and c:d to form a proportion, the equation a*d = b*c must hold true.
For the given ratios, cross-multiply to check:
5 * 9 = 20 * 3
45 = 60
The results of the multiplication are not equal, therefore, the ratios 5:3 and 20:9 do not form a proportion.