Answer:
The constant of proportionality is equal to 4
Step-by-step explanation:
The picture of the question in the attached figure
Let
y ----> the total cost in dollars
x ----> the number of bags of peanuts
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form
or 
To find out the constant of proportionality, we need to take one point from the graph
take the point (1,4)
Find the value of k

substitute the value of x and the value of y
