Corrine wrote temperatures in degrees Celsius and the equivalent temperatures in degrees Fahrenheit. Equivalent Temperatures Celsius –10 5 10 20 Fahrenheit 14 41 50 68 Which explains how Corrine could determine if the temperatures vary directly? Compare the equivalent temperatures as a ratio; if the ratios are equivalent, then the temperatures vary directly. Draw a graph of the temperatures; if the points form a straight line, then the temperatures vary directly. Write an equation that converts one temperature to another; if the temperatures satisfy the equation, then they vary directly. Look for a pattern in the table; if the pattern is consistent, then the temperatures vary directly.