NECO 2001 Mathematics · Question 29
The angle of elevation of the top T of a pole from a point X on the horizontal ground is 32°, if X is 68 m…
Question
The angle of elevation of the top T of a pole from a point X on the horizontal ground is 32°, if X is 68 m away from the foot F of the pole, calculate the height FT of the pole, correct to one decimal place.
- A.128.3m
- B.108.8m
- C.80.2m
- D.57.7m
- E.42.5m
Answer: E. 42.5m
Explanation written with AI and checked against the answer key
Analyze the question: The pole stands vertically on level ground. From X, 68 m from the foot F, the angle of elevation to the top T is 32°. This gives a right-angled triangle XFT with the right angle at F.
- Adjacent side (XF) = 68 m
- Opposite side (FT) = the height we want
- Angle at X = 32°
Concept: Since we have the opposite and adjacent sides, we use the tangent ratio:
tan θ = opposite / adjacent
Solution:
tan 32° = FT / 68
FT = 68 × tan 32°
From tables or a calculator, tan 32° ≈ 0.6249
FT = 68 × 0.6249 ≈ 42.49 ≈ 42.5 m
Answer: The height of the pole is 42.5 m, which is option E.
Tip: Remember SOH-CAH-TOA. When the question gives the adjacent side and asks for the opposite (or the reverse), use TOA, the tangent ratio. A quick sense check: for angles under 45°, tan is less than 1, so the height must be less than the horizontal distance (here, less than 68 m). That immediately rules out A and B.
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