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| Question 43142:  Two planes leave an airport at the same time, one flying due west at 500km/h and the other flying due southeast at 300km/h. What is the distance between the planes two hours later?
 Answer by psbhowmick(878)
      (Show Source): 
You can put this solution on YOUR website! Note: Distance = Speed x Time 
 In 2 hours, the plane travelling to West travels a distance of 500x2 = 1000 km.
 In 2 hours, the plane travelling to South-East travels a distance of 300x2 = 600 km.
 
 If their initial position was the point O then their final positions, after 2 hours, are points A and B respectively.
 
   
 We need to know the length of AB.
 In triangle BCO,  as OB is in South-East direction.
 So,
  = cos(< BOC) =  or
  or
  or
  or
   or OC = 424.264 km
 
 Therefore, AC = AO + OC = 1000 + 424.264 = 1424.264 km
 
 As BCO is a right angled isosceles triangle with
 Now, in triangle ACB, 
Applying Pythagorus theorem,
 
  or
  or
  or
  or AB = 1486.112 km
 
 Hence, the reqd. distance between the two planes after 2 hours is 1486.112 km.
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