Define the containers

Steps

1. Understand the problem.
1. We need a container for radius, area, PI, and radius_squared.
2. radius, area, and radius_squared must be variable and of number type.
3. PI will not change.  It will be a constant container.
4. We need literal contains for "The area of a circle of radius ", " is ", and "." to produce readable output.
   
2. Design a solution.
1. Create a variable container, radius, which will hold number values.
2. Create a variable container, radius_squared, which will hold number values.
3. Create a literal container which will hold the value, "The area of a circle of radius ".
4. Create a literal container which will hold the value, " is ".
5. Create a literal container which will hold the value, " . ". 
6. Create a literal container which will hold the value, 3.14.
7. Create a constant container, PI, which will hold number values.
   
3. Test the solution.