An aeroplane is observed to be approaching the airport. It is at a distance of 10 km from the point of observation on the ground and makes an angle of elevation θ. If the aeroplane is at a height of 8 km above the ground, then which one of the following is correct?
1
0 < θ < 30°
2
30° < θ < 45°
3
45°< θ < 60°
4
60°< θ < 90°