2025 · Q11
A lamp is kept on a vertical pole. The height of the top of the lamp above the ground is 5√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?
Elementary MathematicsGeometry: Lines, Angles and Triangles
- A3 m
- B5 m
- C6 m
- D7 m
Explanation
The pole's base is 0.7 m and 2.4 m from the two perpendicular walls, so its ground distance from the corner is √(0.7² + 2.4²) = √6.25 = 2.5 m. The lamp top is 5√3/2 m above the ground. Hence the distance from the ground corner to the lamp top is √(2.5² + (5√3/2)²) = √(6.25 + 18.75) = √25 = 5 m, option (b).