What value of y makes this proportion true?
15/35 equals y/84

15/35 = y/84

to find what value of y makes the proportion true, you actually just need to solve for y.

15/35 = y/84 ... first, multiply both sides by 84
(15*84)/35 = y
1260/35 = y
36 = y

so, these values are proportional when y = 36. you can check this by getting the decimal of both and seeing if they're equal:
(15/35) = 0.428
(36/84) = 0.428

15/35=y/84

15 times 84 equals 1260.
1260 divided by 35 is 36.

ANSWER: 36