Answer: The constant of proportionality is r = 5.
Explanation:
O, we know that x and y are proportional, this means that:
y = r*x
where r is the constant of proportionality.
we also have the table
x y
7 35
12 60
20 100
Now, we can replace those values in our equation and get, for the first pair:
35 = r*7
r = 35/7 = 5
for the second pair:
60 = r*12
60/12 = 5 = r
So we can conclude that the constant of proportionality is 5.