Answer:
If x and y are in direct proportion, it means that they can be related by a constant ratio. In mathematical terms, this relationship can be expressed as:
(x₁ / y₁) = (x₂ / y₂)
In this case, you are given that when x is 9, y is 45. So, let's use this information to set up a proportion:
(9 / 45) = (15 / y)
Now, cross-multiply and solve for y:
9 * y = 45 * 15
9y = 675
y = 675 / 9
y = 75
So, when x is 15, y is 75.