an airplane flies 200km from city a to city b east,then 200km south from city b to c,and finally 100km northwest to city d.how far is it from city a to city d.in what direction must the airplane head to return directly to city a from city d?

Answer 1

location of c is (200,-200)

location of d
x = 200 - 100 cos 45
y = -200 + 100 sin 45

keep heading NW obviously
distance = a to d:

= 200 sqrt 2 - 100