**Answer:**

[tex]p=0.60w[/tex]

**Step-by-step explanation:**

Let

p ----> the price of a watermelon in dollars

w ---> the weight of a watermelon in pounds

In this problem we have a proportional relationship

Remember that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form [tex]y/x=k[/tex] or [tex]y=kx[/tex]

In a proportional relationship the constant of proportionality k is equal to the slope m of the line and the line passes through the origin

In this problem

[tex]p=kw[/tex]

The value of the constant of proportionality k is the same that the unit rate

**Find out the unit rate**

Divide the total cost by the total weight

[tex]k=\frac{4.38}{7.3}=\$0.60\ per\ pound[/tex]

substitute in the equation

[tex]p=0.60w[/tex]