Use the graph to estimate the amount of milk that would need to be added to make the coffee 90℃. To do this, find the temperature of 90℃ on the y-axis. Then, move straight across using a ruler or straight edge towards the "best fit line". Once you reach the "best fit line" for that temperature, record the mL of milk from the x-axis that corresponds to that point. Graph estimate for the amount of milk that would need to be added to make the coffee 90℃: