This document defines and provides examples of direct variation, which is when one quantity (y) varies directly as another quantity (x). Direct variation can be expressed as an equation y = kx, where k is the constant of variation. The document explains that as x increases or decreases, y will increase or decrease proportionally. It provides examples of finding the constant of variation k from tables of x and y values. It also shows how to use the direct variation equation to find an unknown value when the other variable and the constant k are given.