Answer:
- -0.0018 °F/ft
- the change in boiling point of water per foot of altitude
Step-by-step explanation:
You are given two points ...
... (altitude, boiling point) = (-500, 212.9) and (2500, 207.5).
The slope is ...
... slope = (change in dependent variable)/(change in independent variable)
... = (207.5 -212.9)/(2500 -(-500)) = -5.4/3000 = -0.0018 . . . . °F/ft
Any slope is a "rate of change". Here, the change is °F of boiling point per foot of altitude. That is, the graph says on average increasing the altitude of boiling water by 1 ft decreases its boiling point by 0.0018 °F.
