Question 1·Easy·Linear Functions
Argon is placed inside a container with a constant volume. The graph shows the estimated pressure , in pounds per square inch (psi), of the argon when its temperature is kelvins.
What is the estimated pressure of the argon, in psi, when the temperature is kelvins?
For graph-based linear function questions, start by identifying which axis corresponds to which variable, then locate the given value on the correct axis (here, on the temperature axis). From that point, move along a vertical or horizontal guide line to the graph, then to the other axis to read off the needed value. Ignore the answer choices until after you have read the value from the graph; then simply match your reading to the closest option to avoid being tricked by values that appear on the other axis.
Hints
Match the variable to the correct axis
Identify which axis shows temperature and which shows pressure. Which variable does the problem fix, and which variable do you need to find?
Focus on x = 600
Look specifically at the point where the temperature is kelvins on the horizontal axis. From that value, think about how you can find the matching point on the graph.
Use the graph, not the answer choices, to find y
Once you find , trace up to the line and then over to the vertical axis. Compare the pressure value you see there with the answer choices.
Desmos Guide
Model the line from two clear graph points
From the printed graph, pick two easy-to-read points on the line, such as and where and are temperatures and and are pressures. In Desmos, create a table and enter these as and , then type a line equation that fits them. For example, if your graph clearly shows and the line goes through the origin, you could type y = (6/300)x.
Use Desmos to find the pressure at 600 K
In Desmos, once you have the line equation that matches your graph, type in the temperature value 600 as x = 600 or directly evaluate the expression for . Look at the corresponding -value from the line in Desmos; that -value is the pressure in psi when the temperature is 600 kelvins.
Step-by-step Explanation
Understand what each axis represents
The graph has temperature in kelvins on the horizontal axis and pressure in psi on the vertical axis. The question asks for the pressure when the temperature is kelvins, so we need the -value that corresponds to .
Locate 600 on the temperature (x) axis
On the horizontal axis, find the point labeled . From this point, imagine or draw a vertical line straight up until it meets the graphed line that shows the relationship between temperature and pressure.
Read the corresponding pressure (y) value
From the point where your vertical line at meets the graph, move horizontally to the left to the vertical axis and read off the pressure value. That -value is psi, so the correct choice is 12.