If y is directly proportional to x, then

when x is multiplied by a number, so is y.

 

 

      

 

 

 

 

         

 

 

 

 

 

        

 

 

 

If y is indirectly proportional to x, then

when x is multiplied by a number,

 y is divided by that number, and vice versa. 

 

As one number goes up, the other goes down.

 

                   

 

 

 

 

 

 

 

 

 

 

 

 

 

              

 

 

 

 

 

 

 

 

 

If y is directly proportional to x², then when x is multiplied by a number, y is multiplied by the square of that number.

 

 

 

 

 

 

 

 

 

 

 

 

 

             

 

 

 

 

 

·      Joint Variation