Cloud is related to Number. Number is related to Rate. Rate is related to Proportion. 
Expensive is related to Price. Price is related to Money. Money is related to Knee. 
Cloud <--RelatedTo--> Number <--RelatedTo--> Rate <--RelatedTo--> Proportion 
Expensive <--RelatedTo--> Price <--RelatedTo--> Money <--RelatedTo--> Knee 