The relationship between x and y is proportional. when x is 3, y is 51. what is x when y is 204?

The value of X when Y is 204 is 12

Let the relationship between X and Y be a direct proportion

If Y and X is directly proportional then;

k is the constant of proportionality

If X = 3 and Y = 51

In order to get the value of X if Y is 204, Recall;

Hence the value of X when Y is 204 is 12

Learn more here: link

Determine the constant of proportionality:  Start with the generic form y = kx (for direct proportion).  Insert the given info to find the value of k:

51 = k(3), so that k = 17.  Then the rule here is y = 17x.

Now, if y is 204, 204 = 17x, and x = 204/17 = 12

Summary:  When y = 204, x = 12.