A vertical tower stands on level ground. From a point P, the angle of elevation to the top is 30°. After moving 100 m closer to the tower along the line joining P to the foot of the tower, the angle of elevation becomes 60°. The height of the tower is:
\(50\sqrt3\) meters
Let the tower's height be h. Using the standard result for this configuration: \(h = \dfrac{d}{\cot30^\circ-\cot60^\circ}\), where d=100 m is the distance moved closer.
\(\cot30^\circ = \sqrt3\) and \(\cot60^\circ = \dfrac{1}{\sqrt3}\), so \(h = \dfrac{100}{\sqrt3-\tfrac{1}{\sqrt3}} = \dfrac{100}{\tfrac{2}{\sqrt3}} = \dfrac{100\sqrt3}{2} = 50\sqrt3\).
Hence, the height of the tower is \(50\sqrt3\) metres.
If x is the distance of P from the bottom of the pillar, then consider the following statements :
1. x can take two values which are in the ratio 1 : 3
2. x can be equal to the height of the flagstaff
Which of the statements given above is/are correct?
What is a possible value of tan θ ?
A vertical tower standing on a levelled field is mounted with a vertical flag staff of length 3 m. From a point on the field, the angles of elevation of the bottom and tip of the flag staff are 30° and 45° respectively. Which one of the following gives the best approximation to the height of the tower?
Two poles are 10 m and 20 m high. The line joining their tops makes an angle of 15° with the horizontal. The distance between the poles is approximately equal to
The angle of elevation of the top of a tower from a point 20 m away from its base is 45 °. What is the height of the tower?