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ABCDEF is a regular polygon .Two poles a...

ABCDEF is a regular polygon .Two poles at C and D are standing vertically and subtend angles of elevation `30^(@)and60^(@)` at A respectively .What is the ratio of the heigth of the pole at C to that of the pole at D ?

A

`1:1`

B

`1:2sqrt(3)`

C

`2sqrt(3):1`

D

`2:sqrt(3)`

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The correct Answer is:
To solve the problem, we need to find the ratio of the height of the pole at point C (h1) to the height of the pole at point D (h2). We will use trigonometric relationships based on the angles of elevation given. ### Step-by-Step Solution: 1. **Identify the Angles of Elevation**: - The angle of elevation from point A to pole C is 30 degrees. - The angle of elevation from point A to pole D is 60 degrees. 2. **Set Up the Geometry**: - Let the distance from point A to point C be \( AC = x \). - Let the distance from point A to point D be \( AD = y \). - The height of the pole at C is \( h_1 \) and at D is \( h_2 \). 3. **Use Trigonometric Ratios**: - For pole C: \[ \tan(30^\circ) = \frac{h_1}{x} \] We know that \( \tan(30^\circ) = \frac{1}{\sqrt{3}} \), so: \[ \frac{1}{\sqrt{3}} = \frac{h_1}{x} \implies h_1 = x \cdot \frac{1}{\sqrt{3}} \implies h_1 = \frac{x}{\sqrt{3}} \] - For pole D: \[ \tan(60^\circ) = \frac{h_2}{y} \] We know that \( \tan(60^\circ) = \sqrt{3} \), so: \[ \sqrt{3} = \frac{h_2}{y} \implies h_2 = y \cdot \sqrt{3} \implies h_2 = y \sqrt{3} \] 4. **Determine the Distances**: - Since ABCDEF is a regular polygon, the distances \( AC \) and \( AD \) can be expressed in terms of the side length of the polygon. Let’s assume the side length is \( a \). - For a regular hexagon, \( AC = a \) and \( AD = 2a \) (since D is two sides away from A). 5. **Substitute the Distances**: - Substitute \( x = a \) and \( y = 2a \) into the height equations: \[ h_1 = \frac{a}{\sqrt{3}} \quad \text{and} \quad h_2 = 2a \sqrt{3} \] 6. **Find the Ratio**: - Now, we can find the ratio of the heights: \[ \frac{h_1}{h_2} = \frac{\frac{a}{\sqrt{3}}}{2a \sqrt{3}} = \frac{1}{\sqrt{3}} \cdot \frac{1}{2\sqrt{3}} = \frac{1}{6} \] ### Final Answer: The ratio of the height of the pole at C to that of the pole at D is \( \frac{1}{6} \).
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