12 miles due east and then 5 miles due north; when you sketch east and north make angle of 90 degrees
so, use Pythagorean theorem to find the shortest distance which will be the hypotenuse
x%5E2=12%5E2%2B5%5E2
x%5E2=144%2B25
x%5E2=169
x=sqrt%28169%29
x=13
so, your answer is 13