Ratio: Definition – Examples

When we compare two quantities or numbers and determine “how many times” first number is of second number. 

                                    or
we can say how two quantities are compared with 
each other.

Example:  In a class there are 3 boys and 2 girls.
                 The ratio can be shown in different
                 ways

      1.        Symbol  “:” separate the values,
                 so ratio of boys and girls are 

                                  3 : 2  

      2.        In place of  “:” use the word To
                 The ratio of boys and girls are

                                  3 to 2

      3.        Write to like a fraction,

                                   3/2

 The cost of a pen is $8 and cost of a pencil is  $4.

               The ratio of pen and pencil cost are

                         8 : 4,    8 to 2,   8/2.

              John’s weight is 20 kg and his father’s 
               weight is 60 kg  

              The ratio of john’s weight and his father’s
               weight is

                        20:60,    20 to 60,   20/6.

             The ratio of john’s weight and his father’s
              weight is

                                    20 : 60

             The ratio of john’s father’s weight and join’s
              weight is

                                    60 : 20  

 John’s weight is 20 kg and his father’s weight is 
 60 kg, 

 How many times father’s weight is of john,s weight.

                          It is three times. 

 we can say

           The ratio of john’s weight and his father’s
            weight is

                     20 : 60  =  20/60  =  1/3 

          The ratio of john’s father’s weight and join’s
           weight is

                  60 : 20  =  60/20  =  3/1 

          Two ratios 1:3 and 3:1 are different from 
           each other.

                             The ratio 1:3 is    

          The ratio of john’s weight and his father’s
           weight is 

                        20 : 60  =  20/60  =  1/3 

                             The ratio 3:1 is

           The ratio of john’s father’s weight and join’s
            weight is 

                       60 : 20  =  60/20  =  3/1

          The length of a pencil is 10 cm and length of
           a pen is 5 cm.

           The ratio is length of pencil and pen are

                      10:5,   10 to 5,   10/5

           The ratio is length of pencil and pen are

                       10  : 5  =  10/5  =  2/1

           The ratio is length of pen and pencil are

                      5  : 10  =  5/10  = 1/2

     In each of the above example the numbers are same, but the order in which they are written is difference.

          simply In ratios order is very important..