with Ada.Text_IO; 

with Ada.Float_Text_IO; 

with Ada.Numerics.Generic_Elementary_Functions; 

procedure Circle_Area is 

  Pi : constant Float := Ada.Numerics.Pi; 

    --  Pi is predefined in Ada.Numerics 

  Radius : Float := 12.0; 

    --  Change here to calculate with different areas

  Area : Float := 0.0; 

    --  Recommended, but not mandatory, to initialize variables

begin -- Begins the algorithm here and follows sequentially (unless...)

  Area := Pi* Radius ** 2; 

  Ada.Float_Text_Io.Put(Area); 

    --  Dot notation for elements on a set, in this case a function

end Circle_Area;