C-11-Q013mediumsingle_mcqIf four quantities a,b,c,da,b,c,da,b,c,d form a proportion, the relationship is—aa+b=c+da+b=c+da+b=c+dba:b=c:da:b = c:da:b=c:dcab=cdab = cdab=cdda−b=c−da-b = c-da−b=c−d