Gas is related to Drive. Drive is a synonym of Engine. 
Approve is etymologically related to Prove. Prove is related to Define. Define is a type of Show. Broadcast is a type of Show. 
Gas <--RelatedTo--> Drive <--Synonym--> Engine 
Approve --EtymologicallyRelatedTo--> Prove <--RelatedTo--> Define --IsA--> Show <--IsA-- Broadcast 