If i have 12 cookies and i buy then for one dollar how much is each cookie​

 " $ 0.08 " .

    → Each cookie costs $ 0.08 .

Step-by-step explanation:

1 dollar/ 12 cookie(s) ;

      =  (1/12) dollars per cookies ;

      =  ( 1 ÷ 12) dollars per cookie ;

      = 0.083333333333333 dollars per cookie;

   Round to: 0.08 dollars per cookie;

                 Write as: $ 0.08 per cookie.

     →  Each cookie costs $ 0.08 .

Hope this is helpful!

other answer is correct. i had used the radius of the radius somehow. a website: