Question

The graph of a proportional relationship passes through the points (4,3) and (x,9). Find x.

Answer 1

If x and y are proportional, then y : x = constant.

`(y)/(x)=a\to y=ax`

We have (4, 3) and (x, 9). Substitute:

`(9)/(x)=(3)/(4)` cross multiply

`3x=(9)(4)`

`3x=36` divide both sides by 3

`\boxed{x=12}`