JAMB 1995 · UME · Q35✱✱

Elevation, depression & bearings

A schoolboy lying on the ground 30 m away from the foot of a water tower observes that the angle of elevation of the top of the tower is $60^\circ$ . Calculate the height of the water tower.

Worked solution (try it first)

The height is opposite the $60^\circ$ angle and the 30 m is adjacent, so $\tan60^\circ = \frac{\text{height}}{30}$ .
Multiply both sides by 30: height $= 30\tan60^\circ$ .
Since $\tan60^\circ = \sqrt3$ , the height is $30\sqrt3$ m, option B.

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