Two airplanes leave an airport at the same time. One airplane travels at 400 km/h

and the other at 525 km/h. After 2 hours, the planes are 900 km apart. Determine

the angle between their paths. Hint:

distance = (speed) (time)

912.414

Step-by-step explanation:

The angle

θ

between the directions of motion of planes

θ

=

320

-

200

=

120

∘

The distance

a

traveled by first plane flying at a speed of

150

km/hr

in

3

hrs

a

=

150

⋅

3

=

450

k

m

Similarly, the distance

b

traveled by second plane flying at a speed of

200

km/hr

in

3

hrs

b=

200x3=

600 km

Now, the distance between the planes after 3

hrs will be equal to the side of a triangle opposite to the angle θ=120∘

included by the sides

a

=

450

& b=

600

.

Now, using Cosine rule in the concerned triangle, the distance between the plane after

3

hours is given as