Question

what is direct variation

Answer 1

Direct Variation. Directly Proportional. A relationship between two variables in which one is a constant multiple of the other. In particular, when one variable changes the other changes in proportion to the first. If b is directly proportional to a, the equation is of the form b = ka (where k is a constant).

Answer 2

Two quantities are said to be in direct proportion or variation if they increase or decrease at the same time .
They are in such a way that their ratio is constant.
they can be expressed in the form of variables as,

$\frac{x}{y} = k$
where k is a constant.