What relationship exists between two variables when their ratio is a constant?

If two variables (let us say x and y) have ratios that is constant, therefore we can say that the two variables are directly proportional to each other or in other terms they have a direct variation type of relationship. This takes the form:

x / y = k

where k is a constant of proportionality

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )