PL/SQL Program to Find Area of Circle

PL/SQL Program to Find Area of Circle:

declare
radius float; 
area float;
begin
radius:=:radius;
area:=3.14*radius*radius;
dbms_output.put_line('The area of circle is '||area);
end;

OUTPUT:

Radius is 3
The area of circle is 28.26

PL/SQL Package to find Factorial and Armstrong Number