Answer:
m=22.5
Explanation:
m is proportional to n means there is some constant k such that:
m=kn
If m=5 when n=4 then we have the following equation to solve for our constant k:
5=k(4)
5=4k
Divide both sides by 4:
5/4 =k
So k=5/4 no matter what (m,n) pair they give you where the equation is m=kn.
m=(5/4)n
What is m when n=18?
m=(5/4)(18)
m=(5/2)(9)
m=45/2
m=22.5