An  explorer  is  caught  in  a  white out  (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  5.6 km, but when the snow clears, he discovers that
he  actually  traveled 7.8 km at 50°  north of due east. (a)  How far
and (b) in what direction must he now travel to reach base camp?