A proportional relationship is characterized by a straight line that passes through the origin (0,0) and has a constant ratio between the two quantities being measured.
Looking at the graphs:
- Line 1 starts at (0,2) and does not pass through the origin, so it is not proportional.
- Line 2 passes through (0,0) and appears to increase linearly as time progresses, suggesting a constant rate. Hence, this line represents a proportional relationship.
- Line 3 also passes through (0,0) but does not maintain a constant rate throughout the time intervals.
Therefore, the friend whose graph is a proportional relationship is Friend 2.