text: suppose you travel north for 35 kilometers then travel east 65 kilometers how far  from your starting point?   using the pythagorean theorem, you would be sqr((35^2)+(65^2)) kilometers  shown here:  t=sqr((35^2)+(65^2)) t=sqr(1225+4225) t=sqr(5450) t=73.824 km  got it?  //edit// garypopkin has a good point but i'll assume this is likely for a hs math course and of all probability, its not asking for much more than plane vectors lemme know if its the asking for the earth's surface: its much more complicated, but still possible