An explorer is caught in a whiteout (in which the snowfall is so thick that the ground cannot be distinguished from the sky) while returning to base camp. He was supposed to travel due north for 4.9 kilometer, but when the snow clears; he discovers that he actually traveled 7.8 kilometer at 54 degree north of due east.
(a) Determine how far must he now travel to reach base camp?
(b) Find in what direction must he travel? (counter clockwise from due east)