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A boy 1.5 m tall stands 8.5 m from a lamp post. His shadow is 4.5 m long. The height of the lamp post is
A3.83 m
B4.5 m
C4.33 m
D5 m
Answer & Solution
Correct answer: C. 4.33 m
1. Similar triangles: lamp/(boy distance + shadow) = boy/shadow.
2. lamp/(8.5 + 4.5) = 1.5/4.5.
3. lamp = 13 × 1.5 / 4.5 = 19.5 / 4.5 ≈ 4.33 m.
_Source: NCERT Class 10 Mathematics, Ch 9 "Some Applications of Trigonometry", §9.2_
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