Final answer:
The graph shows a proportional relationship between the radius and circumference of a circle. Measurement inaccuracies and the presence of irregularities can cause the measured values to not be exactly proportional.
Step-by-step explanation:
Question A: The graph shows that there does appear to be a proportional relationship between the radius and circumference of a circle. As the radius increases, the circumference also increases, and vice versa. This relationship can be seen as a straight line on the graph.
Question B: The measured radius and circumference may not be exactly proportional due to experimental errors, measurement inaccuracies, or the presence of irregularities in the circular objects. Additionally, the formula for the circumference of a circle is C = 2πr, where π is an irrational number, so the values obtained for the circumference may not be perfect multiples of the radius.