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Mathematics · 2019
JEE Main · 10 January 2019, Shift 1 · Q89
Consider a triangular plot ABC with sides AB =7 m, BC =5 m and CA =6 m. A vertical lamp-post at the mid point D of AC subtends an angle 30° at B. The…
Consider a triangular plot ABC with sides $\displaystyle \mathrm{AB}=7 \mathrm{~m}, \mathrm{BC}=5 \mathrm{~m}$ and $\displaystyle \mathrm{CA}=6 \mathrm{~m} . \mathrm{A}$ vertical lamp-post at the mid point D of AC subtends an angle $\displaystyle 30$° at B. The height (in m) of the lamp-post is :
Official answer
(4)
$\displaystyle \frac{2}{3} \sqrt{21}$
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JEE Main 2019 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.