Posted by Meenakshi on Thursday, December 13, 2012 at 11:36am.
The pilot of an aircraft flying horizontally at a speed of 1200 Km/hr observes an angle of depression of a point on the ground changes from 30 degree to 45 degree in 15 seconds. Find the height of the aircraft at which it is flying?

maths plse help me..  Steve, Thursday, December 13, 2012 at 11:46am
at 1200km/hr, the plane travels
1200km/hr * 15sec * hr/3600sec = 5km
If the height of the plane is h, and the horizontal distance of the plane from the point on the ground after the 2nd observation is x,
h/x = tan 45° = 1
h/(x+5) = tan 30° = 1/√3
h=x, so,
h/(h+5) = 1/√3
h = 5/(√31) = 6.83 km 
maths plse help me..  Shahare alam, Thursday, November 19, 2015 at 11:53am
6.83