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From the top of a cliff, 200m high, the ...

From the top of a cliff, 200m high, the angle of depression of the top and bottom of a tower are observed to be `30^(@)` and `60^(@)`, find the height of the tower.

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To solve the problem, we will use the concept of angles of depression and some basic trigonometry. ### Step-by-Step Solution: 1. **Understand the Setup**: - We have a cliff that is 200 meters high. - From the top of the cliff, the angles of depression to the top and bottom of the tower are 30° and 60°, respectively. 2. **Draw the Diagram**: - Draw a vertical line representing the cliff (200 m). - Let point A be the top of the cliff, point B be the bottom of the tower, and point C be the top of the tower. - The angle of depression to point C (top of the tower) is 30° and to point B (bottom of the tower) is 60°. 3. **Identify the Right Triangles**: - From point A to point B, we have a right triangle where the height of the cliff is the opposite side and the horizontal distance from point A to point B is the adjacent side. - Similarly, from point A to point C, we have another right triangle. 4. **Using Trigonometry for Triangle ACB**: - For triangle ACB (where angle of depression to C is 30°): \[ \tan(30°) = \frac{200}{x} \] where \( x \) is the horizontal distance from point A to point C. - We know that \( \tan(30°) = \frac{1}{\sqrt{3}} \), so: \[ \frac{1}{\sqrt{3}} = \frac{200}{x} \] - Rearranging gives: \[ x = 200 \sqrt{3} \] 5. **Using Trigonometry for Triangle ADB**: - For triangle ADB (where angle of depression to B is 60°): \[ \tan(60°) = \frac{200}{x'} \] where \( x' \) is the horizontal distance from point A to point B. - We know that \( \tan(60°) = \sqrt{3} \), so: \[ \sqrt{3} = \frac{200}{x'} \] - Rearranging gives: \[ x' = \frac{200}{\sqrt{3}} \] 6. **Finding the Height of the Tower**: - The height of the tower \( H \) can be found by subtracting the height of point B from point C: \[ H = (200 - \text{height at B}) \] - The height at B can be calculated using the triangle ADB: \[ \text{height at B} = 200 - H \] - Using the horizontal distance \( x' \) from A to B: \[ H = 200 - \left(200 - \frac{200}{\sqrt{3}}\right) \] - Solving this gives: \[ H = \frac{200}{\sqrt{3}} \text{ meters} \] 7. **Final Calculation**: - To find the height of the tower, we need to calculate: \[ H = 200 - \left(200 - \frac{200}{\sqrt{3}}\right) = \frac{200}{\sqrt{3}} \text{ meters} \] - Therefore, the height of the tower is: \[ H = 200 \left(1 - \frac{1}{\sqrt{3}}\right) = \frac{200(\sqrt{3} - 1)}{\sqrt{3}} \text{ meters} \] ### Final Answer: The height of the tower is approximately \( 200(\sqrt{3} - 1) \) meters.
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