The stratosphere extends to 50 km above Earth's surface.
The temperature at the top of the stratosphere is -15 °C
If we graph height above Earth's surface (in km) on the x-axis and temperature (in °C) on the y-axis, the point (50, -15) would be on the graph.
The top of the troposphere is located at 20 km. At this point, the temperature is approximately -55 °C. Then, the point (20, -55) would be on the graph.
The slope of the line that passes through points (x1, y1) and (x2, y2) is computed as follows:
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]Replacing with points (50, -15) and (20, -55), we get:
[tex]m=\frac{-55-(-15)}{20-50}=\frac{-40}{-30}=\frac{4}{3}[/tex]The slope is 4/3