Question 166869
Distance(d) equals Rate(r) times Time(t) or d=rt;  r=d/t and t=d/r
Both planes travel for two hours
Distance the north plane travels=150*2=300 mi
Distance the west plane travels=200*2=400 mi
Now we know that the distance apart of these two planes is simply the hypotenuse of a right triangle with with legs 300 and 400 mi respectively
which is immediately recognized as a 3 4 5 right triangle, so the distance apart is 500 mi

CK
300^2+400^2=D^2
90000+160000=D^2
250000=D^2  take sqrt of each side
D=+or- 500 mi disregard the negative value for D


Hope this helps----ptaylor