A proportional relationship is characterized by a constant ratio between two quantities, which is represented graphically as a straight line that passes through the origin (0,0) with a slope (which may be positive or negative but does not necessarily need to be constant).
Based on the descriptions you provided:
- Graph A has a negative slope but does not pass through the origin (indicating a negative relationship).
- Graph B has a positive slope but does not pass through the origin (indicating it does not represent a proportional relationship).
- Graph C is an increasing concave up curve starting at the origin, which suggests a non-linear relationship.
- Graph D is a straight line with a unit slope that passes through the origin.
Therefore, the graph that shows a proportional relationship is:
D