To answer this question, you must first know the Pythagorean theorem
c^2= a^2 + b^2
The c will always be your hypotenuse and the legs are a and b
c^2=68^2 + 80^2
c^2= 4,624 + 6,400
c^2= 11,024
Now square root both sides
answer is 105 mi (104.995 if you want it to be exact)