To determine the slope and y-intercept of a linear graph, you generally need to identify two points on the line. The slope (\(m\)) is calculated as:
\[ m = \frac{\Delta y}{\Delta x} = \frac{y_2 - y_1}{x_2 - x_1} \]
where \((x_1, y_1)\) and \((x_2, y_2)\) are two points on the line.
The y-intercept (\(b\)) is the point where the graph crosses the y-axis (where \(x=0\)).
To determine if the relationship is proportional, we need to check whether the line passes through the origin (0,0). If it does, then the relationship is proportional. This means that the output variable (number of balls thrown) is directly proportional to the input variable (time).
Without the actual graph, I can't provide specific values for the slope and y-intercept or confirm whether it is proportional. However, you can apply the above explanations to analyze the graph whenever you have it in front of you. If you could describe the graph to me or provide the coordinates of specific points, I would be able to help you calculate the slope and y-intercept.