an aircraft is flying at a height of 3400 m above the ground.if the angle subtended at a given

The aircraft takes 10s to go from one point (say A) to the other (say B) and AB subtands an angle of 30^o at the point of observation (say O) .So, ABO forms a triangle.Now let OC be perpendicualr bisector drawn from O to AB(i.e. actually the height).

Then in right trianle, OAC

AC = OC tan 15^o = 3400 x 0.2679 = 911 m

so, AB = 2 x 911 = 1822 m

Now, the speed of aircraft , v = AB / t = 1822 / 10 = 182.2 m/s.