Alicia used $4$ gallons of gasoline to travel $90$ miles.

1. Is this a proportional situation?

2. At the same rate, how far can she travel on a full tank that holds $18$ gallons?

   Hint:

   Set up a proportion problem to find how many miles Alicia can travel with $18$ gallons of gasoline.

   More Help:

   $\frac{90}{4}=\frac{x}{18}$