To graph the proportional relationship between the number of sit-ups and the time taken, we can use the given data points:
The student can do 30 sit-ups in 60 seconds.
The student can do 90 sit-ups in 180 seconds.
In a proportional relationship, the ratio of the two quantities remains constant. In this case, we can find the constant of proportionality, which is the rate at which the student is doing sit-ups.
The constant of proportionality is calculated as follows:
Constant of Proportionality = (Number of Sit-ups) / (Time in Seconds)
For the first data point (30 sit-ups in 60 seconds):
Constant of Proportionality = 30 / 60 = 0.5 sit-ups per second
For the second data point (90 sit-ups in 180 seconds):
Constant of Proportionality = 90 / 180 = 0.5 sit-ups per second
Since the constant of proportionality is the same for both data points, it confirms that the relationship is indeed proportional.
Now, let's create a graph. On the x-axis, we'll represent time in seconds, and on the y-axis, we'll represent the number of sit-ups. We'll plot the two data points and connect them with a line:
The graph shows a linear relationship where the number of sit-ups is directly proportional to the time in seconds, with a constant rate of 0.5 sit-ups per second.