On average, Anna can drive 31 miles on every gallon of gasoline. If she fills up her tank for $2.19 per gallon, how much will it cost her to drive 434 miles?

If Anna can drive 31 miles on every gallon of gasoline, then to drive 434 miles she will need 434/31 =<<434/31=14>>14 gallons.

Since she fills up her tank for $2.19 per gallon, to drive 434 miles it will cost her 2.19*14 = $30.66. Answer: \boxed{30.66}.