# Math Help - Direct Variation

1. ## Direct Variation

First of all, I am new ,so hello.

now to the topic:
is the formula for direct variation y=kx
and could you please post examples?

2. Originally Posted by Russian
First of all, I am new ,so hello.

now to the topic:
is the formula for direct variation y=kx
and could you please post examples?
This is correct. y varies directly as x.

k is called the constant of proportionality or the constant of variation.

3. Originally Posted by masters
This is correct. y varies directly as x.

k is called the constant of proportionality or the constant of variation.

so you use the formula and then plug the answer as k?

4. Originally Posted by Russian
so you use the formula and then plug the answer as k?
Example: d = rt (distance = rate X time)

Let r be the constant of variation.

The distance (d) varies directly as time (t) if r remains constant. In other words, when t increases, d increases. When t decreases, d decreases.

Follow some of the links I gave you and you'll see other examples.

Also, investigate inverse and joint variation as well.

5. Originally Posted by masters
Example: d = rt (distance = rate X time)

Let r be the constant of variation.

The distance (d) varies directly as time (t) if r remains constant. In other words, when t increases, d increases. When t decreases, d decreases.

Follow some of the links I gave you and you'll see other examples.

Also, investigate inverse and joint variation as well.
thank you, masters