Successful is derived from Success. Solution is a type of Success. Solution is a type of Statement. 
Encourage is a type of Inspire. Spirit is etymologically related to Inspire. you are likely to find Spirit in/at/on Imagination. 
Successful --DerivedFrom--> Success <--IsA-- Solution --IsA--> Statement 
Encourage --IsA--> Inspire <--EtymologicallyRelatedTo-- Spirit --AtLocation--> Imagination 