Answer: Hi, in the equation 9*m = 10*n the proportion is 9 to 10, which means that 9 times the number m is equal to 10 times the number n.
So n is proportional to m in the way that n= (9/10)*m
and m is proportional to n in the way that m= (10/9)*n
This means that the proportion can be written as 9 to 10, or 9:10.
