Answer:
The constant of proportionality is 3/4
Explanation:
Here, we want to write the constant of proportionality in the given graph .
To find the constant of proportionality, we need to find the slope of the line.
We can get the slope by using two of the points on the line.
Mathematically, slope of a line m is;
m = (y2-y1)/(x2-x1)
Let (x1,y1) = (120,90) and (x2,y2) = (400,300)
slope will be ( 300-90)/(400-120) = 210/280 = 3/4