Suppose that `y` is directly proportional to `x` .

1) Find the constant of proportionality,` ` ` k`, if `y = 10.4`  when `x = 4` .

Write your answer as a decimal.

`k =` 

2) Using the `k`  from above write the variation equation in terms of `x` .

`y =` 

2) Using the `k`  from above find `y`  given that `x = 19` . Write your answer as a decimal.

`y =` 

If needed, round to the nearest tenth.