We say that A lw where A is the area l is the length and w is the width. The two quantities x the number of hours worked and y the amount paid are related in such a way that when x changes y changes proportionately such that the ratio remains a constant. Now plug in the x - and y -values to find k.
And the formula for direct variation is y kx where k represents the constant of variation.
In this lesson students learn that if each y value in a function is the result of multiplying each x value by the same number then the function is an example of direct variation. If y varies directly as x and y 10 when x 5 find k and write an equation that expresses this variation. If I buy 10 gallons the price is 30. Given that x and y vary directly write the equation relating x and y if x 3 when y 24.