Answer:
The constant of proportionality is the number that you have to multiply x by to get y. So to find that number based on a graph , you need to look at the different points that are plotted on the graph. Then, you need to write down those points into a x and y table. Once you do that you can look at your numbers and see what the numbers are being multiplied by.
Step-by-step explanation:
Example:
Say my graph had points of
x y
0 0
1 3
2 6
You have to multiply 3 by 1 to get 3, and 3 by 2 to get 6.