A fabric store prices cotton fabric using a proportional relationship between the length of fabric (in yards) and the cost in dollars. If 0.2 yards of fabric costs $1.50, what is the constant of proportionality?
Let's call the constant of proportionality "k".
We know that 0.2 yards of fabric costs $1.50.
So we have the equation 0.2k = 1.5.
To find k, we can divide both sides of the equation by 0.2: k = 1.5 / 0.2.
k = 7.5.
Therefore, the constant of proportionality is 7.5.