Constant of proportionality from a graph point

The line goes through the origin, so divide the point's y by its x.

1. The graph of a proportional relationship is a straight line through (0, 0) and (4, 20). What is the constant of proportionality?
2. The graph of a proportional relationship is a straight line through (0, 0) and (10, 90). What is the constant of proportionality?
3. The graph of a proportional relationship is a straight line through (0, 0) and (7, 70). What is the constant of proportionality?
4. The graph of a proportional relationship is a straight line through (0, 0) and (6, 66). What is the constant of proportionality?
5. The graph of a proportional relationship is a straight line through (0, 0) and (4, 8). What is the constant of proportionality?
6. The graph of a proportional relationship is a straight line through (0, 0) and (2, 10). What is the constant of proportionality?
7. The graph of a proportional relationship is a straight line through (0, 0) and (9, 135). What is the constant of proportionality?
8. The graph of a proportional relationship is a straight line through (0, 0) and (9, 108). What is the constant of proportionality?
9. The graph of a proportional relationship is a straight line through (0, 0) and (6, 72). What is the constant of proportionality?
10. The graph of a proportional relationship is a straight line through (0, 0) and (3, 51). What is the constant of proportionality?
11. The graph of a proportional relationship is a straight line through (0, 0) and (4, 36). What is the constant of proportionality?
12. The graph of a proportional relationship is a straight line through (0, 0) and (4, 40). What is the constant of proportionality?
13. The graph of a proportional relationship is a straight line through (0, 0) and (13, 182). What is the constant of proportionality?
14. The graph of a proportional relationship is a straight line through (0, 0) and (3, 42). What is the constant of proportionality?
15. The graph of a proportional relationship is a straight line through (0, 0) and (14, 154). What is the constant of proportionality?
16. The graph of a proportional relationship is a straight line through (0, 0) and (16, 96). What is the constant of proportionality?
17. The graph of a proportional relationship is a straight line through (0, 0) and (20, 500). What is the constant of proportionality?
18. The graph of a proportional relationship is a straight line through (0, 0) and (12, 264). What is the constant of proportionality?
19. The graph of a proportional relationship is a straight line through (0, 0) and (19, 247). What is the constant of proportionality?
20. The graph of a proportional relationship is a straight line through (0, 0) and (5, 15). What is the constant of proportionality?