So you need to make out the lengths for the triangle. For the height, you can subtract the short length (100) from the longer length (1250) to get the height of the triangle. The base is the length at the very top, 75. So right now you have 150 for height and 75 for the base. Now use the formula to get 75 root 5.
She should bring $320. 120+45+65+30x2+30=320. 120 is on hotels. 45 is about gas for the car. 65 is on food. The ticket price a day is $30, and if Rachel is going twice, then it is 30x2, or 30+30.