Explain the concept of direct variation.

Explanation

Direct variation is a relationship between the two variables in one variable is equal to constant times the other variable.
This means, one variable varies directly with the other variable.
For example: `a=3b`
Here, the equation,`a=3b` is a direct variation where `a` varies with `b`.
So, for different values of `b`, we will different values for `a`.