Two airplanes leave an airport at the same time, one going northwest (bearing 135°) at 421 mph and the other going east at 384 mph. how far apart are the planes after 2 hours (to the nearest mile)?

I am not sure if I am correct.
I think that the angles did not help to solve the problem, ( it makes an obtuse angle)
and the unit rate is 421 mph and 384 mph.

2*421+384*2= 1610 miles
or
2 (421+384)= 1610 miles

1610 miles