Calc
posted by Jake .
Find the constant of proportionality for the following situation: "y is jointly proportional to x and z and inversely proportional to w."
w=2, x=5, y=4, and z=9
So i think the equation is y=xz/w
But what is the constant of proportionalit supposed to mean?

You're almost right.
y = kxz/w, where k is the constant of proportionality.
Plugging in your values,
4 = k*5*9/2
8 = 45k
k = 8/45