What is the constant of proportionality for the relationship shown on the table.

The constant of proportionality = 2

Step-by-step explanation:

Two quantities P and Q are said to be proportional  if for  P ∝ Q iff

Here, k = Proportionality Constant

Now, here given

Case 1: x = 2, y = 1

So,

Case 2: x = 4, y = 2

So,

Case 3: x = 6, y = 3

So,

Case 4: x = 8, y = 4

So,

So, in each case we observe that the value of k = 4

Hence the constant of proportionality = 2

expression #3 is not equivalent. the others are.