JAMB 2012 · UTME · Q36

A man stands on a tree 150 cm150\text{ cm} high and sees a boat at an angle of depression of 74∘74^\circ. Find the distance of the boat from the base of the tree.

Worked solution (try it first)
  1. The angle of elevation of the man from the boat is also 74∘74^\circ (alternate angles), so tan⁡74∘=150d\tan74^\circ = \frac{150}{d}.
  2. Rearrange: d=150tan⁡74∘d = \frac{150}{\tan74^\circ}
    =1503.487= \frac{150}{3.487}.
  3. So d≈43d \approx 43 cm, option B.

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