Jen's car used 10 gallons of gas to travel 300 miles. How many miles did her car travel per gallon of gas?

I’m pretty sure you divide 300 miles by 10 gallons-which would give you 30 miles per gallon.

Use pythagorean’s theorem and find the missing side lengths of the two smaller triangles and add them together
13^2 - 12^2 = 5
15^2 - 12^2 = 9
5+9 = 14
14 is the length of each side of the square
14^2 + 14^2 = 19.8
19.8 is the diagonal length of the inside if the square