A lamp is kept on a vertical pole. The height of the top of the lamp above the ground is \frac{5\sqrt{3}}{2} m. The perpendicular distances of the bottom of the pole from two adjacent walls meeting perpendicularly are 0.7 m and 2.4 m. What is the distance of the top of the lamp from the corner point of the walls on the ground?
- A. 3 m
- B. 5 m ✓
- C. 6 m
- D. 7 m
Correct Answer: B. 5 m
Explanation
Distance from the corner to the pole's base is \sqrt{0.7^2 + 2.4^2} = 2.5 m. Using Pythagoras in 3D, the distance from the top is \sqrt{h^2 + d^2} = \sqrt{18.75 + 6.25} = \sqrt{25} = 5 m.
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