A vertical tower stands on level ground

MATHEMATICS · Multi-part · CBSE · Mathematics · Applications of Trigonometry · Applications of Trigonometry

Problem

A vertical tower stands on level ground. From point A the angle of elevation of the top of the tower is

\theta

. After walking

40\,\text{m}

straight towards the tower to point B, the angle of elevation becomes

(90^\circ-\theta)

. (i) Draw a neat labelled diagram to represent the above situation. (ii) Using the diagram, express the height

h

of the tower in terms of

\theta

. (iii) Calculate

h

when

\theta = 28^\circ

. (Take

\sin 28^\circ = 0.4695

and

\cos 28^\circ = 0.8829

, correct to four decimal places.)