The graph of a proportional relationship is a straight line that passes through the origin.
Proportional quantities can be described by the equation y = kx, where k is a constant ratio.
Use the graph to determine if there is a proportional linear relationship between a temperature in degrees Fahrenheit and a temperature in degree Celsius. Explain your reasoning. 


You can tell that the relationship is not directly proportional by looking at the graph. The graph is a straight line, but it does not pass through the origin. So, the relationship is not directly proportional.