A 2-column table with 4 rows. Column 1 is labeled Gallons with entries 2, 4, b, 10. Column 2 is labeled miles with entries 56, a, 168, c. Alexa is planning to drive across the United States in her car. She started filling out the table showing how far she can travel for each gallon of gas that she uses. Find the missing values using the constant of proportionality of 28 miles per gallon. a = b = c =