Sacred is related to Holy. Holy is etymologically related to Whole. Fraction is part of Whole. Fragile is etymologically related to Fraction. 
Informal is related to Seat. Seat is a type of Device. 
Sacred <--RelatedTo--> Holy --EtymologicallyRelatedTo--> Whole <--PartOf-- Fraction <--EtymologicallyRelatedTo-- Fragile 
Informal <--RelatedTo--> Seat --IsA--> Device 