Answer:
1. Not proportional.
2. k = 0.5
3.

4.

Explanation:
The constant for any proportionality relation is given by
.
Therefore, for the pair of values (2,0), k = 0, hence, the relation is not proportional.
Now, for the peir of values (4,2),
.
Now, for the pair of values of x and y, (6,4), the value of
Finally, for the pair of values of x and y, (8,6), the value of
(Answer)