. Sarah drove 77 miles on 3.6 gallons of gas. If her car holds 15 gallons of gas, which proportion would she use to find out how far she can drive her car on a full tank of gas? a. 3.6/15 = x/77 c. 3.6/77 = x/15 b. 77/x = 15/3.6 d. 77/3.6 = x/15