Calculate the constant of variation if y varies directly as x.

You have not provided the complete question (value of y at a certain value of x), therefore, I cannot give u a specific final answer. However, I can explain how to solve this problem and you can apply on the numbers you have.

y varies directly with x means that as x increases, y also increases and vice versa.
This can be represented by the following equation:
y = kx
where k is the constant of proportionality.

Solving this for k, we would find that:
k = y/x

Examples:
If we are given that y = 4 at x = 2, then:
k = y/x = 4/2 = 2
If we are given that y = 1 at x = 3, then:
k = y/x = 1/3
In general, if we are given that y = a at x = b, then:
k = a/b

Hope this helps :)