Question

An aeroplane leaves an airport and flies due north at a speed of 1000km per hour. At the same time, another aeroplane leaves the same airport and flies due west at a speed of 1200 km per hour. How far apart will be the two planes after` 1 1/2`  hours?

Answer 1

 

Let A be the first aeroplane flied due north at a speed of 1000 km/hr and B be the second aeroplane flied due west at a speed of 1200 km/hr  

Distance covered by plane A in` 1 1/2 hours=1000xx3/2=1500km` 

Distance covered by plane B in `1 1/2 hours = 1200xx3/2=1800 km` 

Now, In right triangle ABC
By using Pythagoras theorem, we have 

`AB^2=BC^2+CA^2` 

=(1800)^2+(1500)^2 

=3240000+2250000 

=5490000 

∴  `AB^2=5490000 ` 

⇒` AB=300sqrt61m` 

Hence, the distance between two planes after `1 1/2 house  is  300 sqrt61m`