Check my answer? given the proportion a/b = 8/15, which ratio completes the equivalent proportion a/8 = ? my 15/b @kirbylegs

I think you have it upside down.
When you solve a proportion, you cross multiply. You can have the same proportion just by interchanging 8 and b

a/8 = b / 15 When you cross multiply, you get
15a = 8b Try the given proportion to see what happens

38 dollars is your answer.