Sectieoverzicht

  • Direct proportion

    If one quantity increases as another quantity increases or decreases as the other decreases then they are directly proportional. For example, as the number of items you buy increases the amount you pay increases too. So, the numbers of items and cost are directly proportional.

    Two quantities \(x\) and \(y\) are in direct proportion if the ratio \(x:y\) is always the same.
     

    Indirect proportion

    If one quantity decreases as another quantity increases then they are inversely (or indirectly) proportional. 

    Two quantities \(x\) and \(y\) are indirectly proportional when their product \(xy\) is constant.

    Proportion is also referred to as variation. In the next video you will go over many examples to learn to identify direct or indirect proportion.

      

    Check your understanding of direct and indirect proportion by trying the activity: Recognise direct and indirect variation. [Edit: I suggest putting this activity in a separate box with a link]