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NDA 2025 Maths · Mathematics · Heights and Distances · medium

A man whose eyes are 1.5 m above the ground stands 20 m from a building and sees its top at an elevation of 60^°. The height of the building is

Single correct option

A man whose eyes are 1.51.5 m above the ground stands 2020 m from a building and sees its top at an elevation of 60∘60^\circ. The height of the building is
  1. A. 20320\sqrt3 m
  2. B. (203+1.5)\left(\dfrac{20}{\sqrt3}+1.5\right) m
  3. C. 21.521.5 m
  4. D. (203+1.5)(20\sqrt3+1.5) m
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Answer: (D) (203+1.5)(20\sqrt3+1.5) m

The part of the building above eye level is 20tan⁡60∘=20320\tan60^\circ=20\sqrt3 m. Add the eye height 1.51.5 m to get 203+1.520\sqrt3+1.5 m. Using tan⁡30∘\tan30^\circ gives the distractor with 203\frac{20}{\sqrt3}.
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Original question written in the NDA 2025 Maths pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake