Sad is related to Unhappy. Unhappy is a synonym of Low. Low is a synonym of Mean. 
Toy is related to Mobile. Mobile is a type of Sculpture. Statue is a type of Sculpture. you are likely to find Statue in/at/on Museum. 
Sad <--RelatedTo--> Unhappy <--Synonym--> Low <--Synonym--> Mean 
Toy <--RelatedTo--> Mobile --IsA--> Sculpture <--IsA-- Statue --AtLocation--> Museum 